Journal of the Institution of Locomotive Engineers
Volume 27 (1937)
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Mills, F. (Paper No. 363)
Some factors affecting locomotive design in Western Australia. 2-23. Disc.:
23-33; 458-9.
28th Meeting of the Western Australian members was held in the Railway
Institute, Perth, Western Australia, on Friday, 28 August 1936, at 8 p.m.,
the chair being taken by J.W.R. Broadfoot.
3ft 6in gauge; 4538 route miles mainly of very light track, nearly half of
which was 45lb/yard and the remainder 60lb/yard.
Clarke, C.W. and Bhote, M.D. (Paper No.
364)
Reflections on the detail design of Indian Railway Standard Locomotives.
34-53. Disc.: 53-68. 12 diagrs.
Ordinary General Meeting of the Western Branch of the Indian and Eastern
Centre held at Bombay, on Friday, 13 September 1935: the chair being taken
by Mr. A. Richardson, Chairman of the Western Branch. The Chairman introduced
Messrs. C.W. Clarke and M.D. Bhote, Joint Authors. The Paper was read by
Mr. Bhote and Mr. Clarke gave a commentary on the slides shown on the screen.
This was followed by a Discussion
In presenting this Paper the Authors have no desire to make destructive
criticisms of existing I.R.S. locomotive designs, but to put before this
meeting certain suggested modifications of details, some of which might perhaps,
with advantage, be incorporated in future standard designs. It is hoped also
that the discussion will produce a symposium on the subject, from which many
useful ideas may emanate. Certain suggestions have of course developed since
the designs were first evolved in 1926.
The first batches of the Indian Railway Standard Locomotives have now been
in service over eight years. At the outset, it will be agreed that they have
given very good service. On the broad gauge systems they run 5,000 miles
per month regularly, and for goods service can show a figure of over 5,000,000
ton miles hauled per month per locomotive. The cylinder performance gives
about 20 ta 22 pounds of steam per I.H.P. hour. The coal consumption as
determined by dynamometer car trials, is about 3.5 pounds of coal per drawbar
horse power per hour. At a first glance, this figure might seem unduly high,
when the corresponding types of English and American locomotives burn only
24 pounds of coal per drawbar horse power per hour, but if it is remembered
that English coal gives about 14,000 B.Th.U.s per pound, whereas the Indian
coals used only averaged 1.2,000 B.T
Considered wheels, axleboxes, piston valves, cylinder covers, slide bars,
motion girders, motion bushings, boiler belly stays, spring compensating
gearv and smokebox blast arrangements. Advocated Baker valve gear as there
are no sliding pairs; all joints are pin joints and the valve rod has no
fixed relationship to the design of gear and is particularly adaptable for
standardization on different classes of locomotive; also considered material
for piston valve liners; ashpans and spring compensating gear, and smokebox
saddles.
Discussion C.F. White (54-5): The Authors have considered
the matter of bearing spring compensation as an effort to overcome the
irregularities of poor track, and I am entirely in agreement with them that
the compensation makes no difference in practice, although it looks well
in theory, except in relation to the bending moments in the frames. That,
I venture to suggest, is because bad riding is a very complex subject governed
by several other factors in addition to weight distribution. The subject
of rough riding needs no introduction to any G.I.P. railwayman, because our
X A I I type came into great prominence in that respect in 1930 due to No.
2204 derailing at high speed near Tadali on the Warda-Ballershah section,
and the subsequent experiments and alterations gave the mechanical department
a lot of extra work. In this connection I would like to bring to the notice
of this meeting two Interesting derailments which have occurred in England
fairly recently in which L.M.S. 0-6-4 tank engines were concerned.
You may be thinking at this moment that no tank engine can be compared with
an XA/1 , but I find from Colonel Mount’s report on the Ashton-under-Hill
and Moira derailments of February 25th and March-20th this year, that both
the engines (Nos. 2023 and 2011) had cartazzi boxes on their leading coupled
wheels and, of course, a bogie under the coal bunker. This class of engine
was used on branch lines for both Up and Down trains without turning, so
they were often bogie leading and cartazzi trailing the same as our XA class.
After the derailment of engine No. 2023 at Ashton on February 25th, in which
the driver was killed, Colonel Mount took a trip on the footplate of No.
2011, which Is the same class, and this is his report:-
‘‘ The trip clearly illustrated how sympathetic this engine was
to track defects, and riding on the footplate obviously afforded a rapid
means of examining the road. On two occasions oscillation developed which,
in my opinion, might have rapidly increased to a dangerous extent had speed
been a little higher or the track less well maintained.” Five days after
Colonel Mount’s trip on No. 2011 she derailed near Moira and at that
time she is reported to have been travelling at between 55-60 m.p.h.
Later on Colonel Mount concluded his Ashton-under-Hill accident report as
follows:-
“ Having regard to the foregoing considerations, and to the circumstances
of this derailment, it was decided to make a trial under tpe following altered
conditions-viz., the replacement of the leading axle cartazzi boxes and of
the coil springs by standard type boxes and laminated springs and the replacement
of the bogie by a standard bogie with side bolsters as used in the new 2-6-4
type tank engines. As a result comparative tests at speeds varying from 35
to 60 m.p.h., with one engine so modified and another not altered, were carried
out a few days after the derailment at Moira on a straight length of second
class track. The conclusion was reached that the unmodified engines were
not suitable for working trains at speeds over 45 m.p.h., and indeed I was
informed that severe oscillation was experienced at no more than 50. m.p.h.,
the passage of the engine causing some track damage. On the other hand, I
understand that the alterations undoubtedly made for improvement, oscillation
and roll being damped out, so that even when running at 60 m.p.h. the riding
was satisfactdry.” As a direct result of these two derailments, and
the subsequent trial with a modified engine, all the 40 class 3, or 2,000
class, of superheater 0-6-4 tank engines have been taken out of passenger
service and a small number have been left in goods traffic for the time being
subject to a maximum speed of 45 m.p.h.
The cartazzi radial boxes and slides were originally designed by a loco.
superintendent of the G.I.P. Railway, about 55 years ago, specially for
negotiating the severe curves on the Kasara-Igatpuri section for which they
are emineotly suitable, because there is no building up of resistance to
lateral movement in proportion to lateral displacement of the wheels. In
the common type of radial, lateral movement is controlled by springs which
build up a resistance in direct proportion to lateral displacement.
From what has occurred recently in England and on the G.I.P., it appears
to me that the cartazzi boxes and slides were never intended for use at more
than 45 m.p.h. So our future I.R.S. passenger engines should be fitted with
a radial truck instead of cartazzi boxes and slides.
Campbell, J. (Paper No. 365)
Rail cars — notes on their introduction, design and operation (with
special reference to Argentine condition). 70-135. Discussion. 135-84.
Page 131: notes that the GWR diesel railcars were based on the AEC
Q type of bus.engine. Notes local operating costs.
Journal No. 138 (March-April)
The Institution's Annual Dinner, 1 April 1937. 185-96.
Nineteenth Annual Dinner of the Institution held at the Trocadero
Restaurant, London., The President (W.A. Stanier), who had recently returned
from India, was in the chair, and there were 412 members and guests present,
which number again established a record. The chief guest of the Institution
was Sir Josiah C. Stamp, (Chairman, L.M.S. Rly.), and others present were
Robert Holland-Martin, (Chairman, Southern Rly.), Sir Ralph Wedgwood, (Chief
General Manager, L.N.E.R.), Hon. S. M. Lanigan-O’Keefe, (High Commissiuncr
for Southern Rhodesia), Sir John E. Thornycroft, (President, Institution
of Mechanical Engineers), Sir Alexander Gibb, (President, Institution of
Civil Engineers), W. V. Wood (Vice-President, L.M.S. Rly.), R. E. L. Maunsell,
M.A., C.B.E. (Past-President), Lieut.-Cal. A.H.L. Mount (Ministry of Transport),
W. K. Wallace (President, Permanent Way Institution), H. M. Proud (President,
Institution of Railway Signal Engineers), Loughnan St. L. Pendred, Brig.-General
Magnus Mowat, (Secretary, Institution of Mechanical Engineers), Dr. R. P.
Wagner (Deutsches Reichsbahn), H. T. Young (President, Institution of Electrical
Engineers), and Mr. K. W. Bridges.
Hancock, J.S. (Paper No. 366)
Locomotive feed-water treatment. 198-221. Disc.: 221-49.
Third Ordinary General Meeting of the Session 1936-37 was held at
the Institution of Mechanical Engineers, Storey's Gate, London, on Wednesday,
the 25 November, 1936, at 6 p.m., J. Clayton, M.B.E., Vice-Presbdent, occupying
the chair. Abstract fromm Locomotive
Mag, 1936, 26, 395-8
After pointing out that chemical treatment of feed water for locomotive boilers
has not made the progress that has been made in the treatment of feed. water
for all kinds of stationary boiler plants, It was agreed that the locomotive
boiler withstands the effects of unsuitable water in a remarkable manner,
and the development of chemical treatment that has taken place in recent
years is almost entirely due to the need for establishing more eoonomical
working conditions.
It is customary to classify waters in terms of "hardness," an expression
denoting the amount of scale-forming salts present in a water. Surface waters
are usually not very hard, but most well waters contain considerable quantities
of scale-forming salts.
The impurities contained in natural boiler feed waters are responsible for
three conditions affecting the maintenance and operation of the locomotive,
namely, scale, corrosion and priming.
Deposition of scale.-The continual evaporation of hard waters in
locomotive boilers results in rapid accumulation of scale and sludge and
leads to frequent stoppages for boiler cleaning.
The usual practice in a hard water district is to withdraw locomotives from
service every 25,000 to 50,000 miles for boiler cleaning, an operation which
requires the removal of a large number of tubes to enable the accumulated
sludge and scale to be cleaned out. This operation is repeated when the engine
goes into the workshops for a "service" repair, while at a "general" repair
which is carried out at every 100,000-120,000 miles the boiler is removed
from the frame and a new or repaired boiler takes its place. Other ill- effects
of hard water are scaling up of internal injector pipes, collapsing of tubes
and leaking of tubes and firebox stays. The decrease in boiler efficiency
due to the presence of scale and sludge is appreciable but not excessive.
From data available from tests carried out at various stages of the life
of a large locomotive boiler, it appeared that the loss in boiler efficiency
after working for over 12 months on hard water did not exceed 3 per cent.
The heat conductivity of the various kinds of scale is, however, a matter
of some importance, since the presence of a low conductivity scale may lead
to over-heating of the metal. Hard, compact scales have the slightest
conductivity, and loose, porous scales and sludges the lowest. It is fortunate
that in a locomotive boiler the dense scale is deposited on the firebox plates
and the porous scale at the smokebox end. Where over- heating of firebox
plates has occurred, the cause has usually been found to be an accumulation
of sludge in the narrow water spaces at the sides of the firebox.
Corrosion. Corrosion is a more important factor than scale in the
ultimate life of a boiler. All the steel components, the tubes, roof stays,
barrel and smokebox tube plate are subject to corrosion, the tubes usually
suffering most severely. Corrosion takes place readily in boilers using soft
natural waters. Corrosion in boilers is serious because it rarely takes the
form of a general uni- form rusting of the entire surface of the metal but
is confined to intensive attack at a few points. There are apparently three
types of corrosion:-
(1) Formation of isolated pits along the top of the tube, usually at the
smokebox end. This form of corrosion is frequently met with in districts
where the water supplies are of the surface type, and form little or no scale
in the boiler. The life of tubes subject to isolated pitting is gener- ally
from two to four years, and failure occurs through penetration of the metal
at one of the pits.
(2) Localised corrosion close to the copper firebox tube plate. In this case
the attack is not confined to the top of the tube, but continues right round
it. "Grooving" appears to+take place more rapidly than pitting, and grooved
tubes fail generally after two to three years' service either by penetration
at one or more points or by complete fracture around the ring. It is not
uncommon to find grooving and pitting taking place on the same tube.
(3) The third type is certainly the most rapid of all forms of boiler corrosion
and may take place even under a fairly heavy coating of scale. It is usually
confined to the firebox end of the tube and is likely to occur if the feed
water is introduced into the boiler just in front of the firebox tube plate.
It appears from a consideration of the conditions under which the various
types occur in locomotive boilers, that corrosion is essentially a chemical
process involving as the primary factor the dissolved oxygen introduced by
the feed water. Calcium, magnesium and sodium salts, in the absence of oxygen,
do not cause corrosion, but if present in sufficient concentration appear
to accelerate the corrosion rate if oxygen is present. The danger that exists
if oxygen is allowed to enter a boiler is fully recognised by the operators
of high pressure stationary boiler plants, who take the utmost precautions,
by mechanical and chemical means, to remove oxygen from the feed water. Since
dissolved oxygen is such a vital factor, it is evident that the manner in
which the feed water is introduced into the boiler is of great importance.
A common method of introducing the feed water into the boiler is through
an internal submerged pipe running from the back plate to within 2-3 feet
of the smokebox tube plate. The oxygen is thus liberated under the water
surface and brought into direct contact with the boiler tubes. In boilers
fed in this manner corrosion usually takes the form of isolated pits at the
smokebox end of the tubes. The tubes of boilers fitted with the Churchward
"top feed" apparatus are invariably free from corrosion, and there is no
doubt that almost complete liberation of the oxygen takes place in the steam
space during the passage of the water over the trays. In a hard water district
there is danger that the distributing trays will become blocked with scale,
so that the apparatus does not function, and frequent cleaning is necessary.
The primary object of a feed water heater is to utilise exhaust steam, but
the open type of feed water heater has a further advantage in being able
to expel 80-90 per cent. of the dissolved oxygen from the feed water. An
increase in the life of tubes from one year to over four years was obtained
some years ago on an American railroad by fitting open type feed water heaters.
Priming. It has long been recognised that the locomotive boiler is
particularly susceptible to a condition which is known in this country as
"priming" and in America as "foaming." These terms unfortunately have never
been properly de- fined, being used in power station plant operation to indicate
a light carry-over of boiler water, but by locomotive engineers to mean a
very heavy carry-over. Steam generated from probably every locomotive boiler
contains a small percentage of boiler water through the entrainment of small
drops thrown into the steam space by the bursting bubbles. The amount of
carry-over depends upon the size of the drops, the velocity of the steam
leaving the water surface, and the distance from water surface to steam outlet.
In addition to the continuous carrying-over of a small quantity of water,
locomotive boilers frequently indulge in short bursts of "priming" in which
sufficient water is carried over with the steam to pass unchanged through
superheater elements and cylinders to the chimney. "Priming" invariably occurs
in bursts lasting from a few seconds to a few minutes, during which the water
level in the gauge glass will drop by two or three inches. The amount of
boiler water carried over during priming is usually about 40-50 per cent.
by weight of the mixture of steam and water; in the case of a boiler generating
300 lb. of steam per minute an additional 300 lb. of water per minute may
be carried over during priming. On superheater engines priming entirely destroys
the superheat. During a burst of priming at speed the running of the engine
is not appreciably affected, but priming at starting often results in time
lost and occasionally in the failure of the engine to get away with its train.
Excessive priming increases the maintenance of locomotives, since it leads
to blowing regulator valves, glands and superheater element joints, and not
least, to increased washing out and decreased engine availability.
It is obvious that "priming" depends upon a number of factors, namely, depth
of steam space, rate of evaporation, and the condition of the boiler water.
In the case of a locomotive boiler in which the distance from water level
at half glass to bottom of steam dome is 10 in.', the lift at full regulator
is at least 5 in. with pure water, so that the working steam space is actually
not very large. The lift is proportional to the velocity of the steam leaving
the water surface, the velocity being determined by the total evaporation
(i.e., amount of regulator opening) and the surface area of the boiler water.
Carrying an unnecessarily high water level diminishes the working steam space
and is responsible for innumerable cases of priming which would not have
occurred with a normal water level.
Feed Water Treatment. Chemical treatment of locomotive feed water
has come rapidly to the fore during the past 20 years, first in America and
recently in this country. The earliest attempts at improving the quality
of locomotive feed water on English railways were made between 1890 and 1900,
when water softening plants were erected at a number of points where unusually
hard waters had to be used. One of the earliest of these plants, erected
on the Midland 'Railway at Derby in 1890, is stil1 operating. In those days
the object of water treatment was simply to remove scale-forming impurities.
To-day, as the result of wider experience, it is realised that economies
in boiler maintenance are obtainable not merely by preventing the deposition
of scale, but by extending the life of the boiler through the reduction of
corrosion to a minimum. Correct feed water treatment must, therefore, condition
the water so that on evaporation in the boiler it will neither deposit scale
nor cause corrosion. Experience has also taught us that a mixture of softened
and unsoftened waters is invariably a corroding water and that water treatment,
to be successful, must be applied not merely to a few hard waters, but to
all the feed water entering a locomotive boiler. The prevention of corrosion
by removing the oxygen from the feed water is not feasible either by chemical
or mechanical means, and it is necessary therefore to look elsewhere for
a suitable remedy. A method of preventing boiler corrosion by chemical treatment
of the feed water exists and has been used with success by American railroads
for the past 15 years. This consists in treating the feed water with suitable
chemicals so that a small quantity of free caustic soda remains at all times
in solution in the boiler water. In America prior to 1920, when the rule
of softening was not to soften below 4 degrees, the average life of steel
fireboxes was 4-5 years, and , of tubes 2-3 years. The average life of tubes
and fireboxes at the present time is approximately 12 years, as the result
of treating the bulk of the feed water.
Water Treatment and Locomotive Operation. Softening of locomotive
feed water invariably re- sults in priming, especially if the water is reduced
to a low degree of hardness by the use. of lime and the maximum dosage of
soda ash. Since "priming" interferes with the running of trains it must be
eliminated at all costs and this is often done by eliminating the amount
of soda ash used at the water softening plants, thus providing a water which
is only partially softened. Alternatively, priming may be eliminated by reducing
the boiler washing out or water changing mileage. The effect of water softening
upon the mileage which can be run before priming commences is very great.
For example, it was necessary, following the introduction of water softening
on a section of a British railway, to carry out changes of boiler water every
500 miles in addition to the customary boiler washout at 2,500 miles. If
the rate of evaporation and the working water level remain fairly constant,
priming can be brought about in one way only, i.e., by raising the sodium
salts in the boiler water to the priming concentration which in the case
of locomotives in this country, varies usually from 150 grains per gallon
for small engines to 200 grains per gallon for large passenger engines, although
instances of higher concentration are sometimes reported. When the critical
concentration of soluble salts is reached priming takes place intermittently
and sufficient boiler water is carried away with the steam to prevent further
increase in the concentration. The mileage which can be run before priming
commences depends upon the rate at which the sodium salts accumulate in the
boiler, i.e., upon the amount of sodium salts in the feed water and the rate
of evaporation. In the case of a boiler whose water capacity is 1,500 gallons
and average evaporation 30 gallons per mile, feJ with well water containing
4-5 grains per gallon of soluble salts, the critical priming concentra:tion
of 200 grams per gallon will be reached at 2,200 miles after washing out,
provided no carry-over is taking place. In practice, however, it frequently
happens that the small percentage of carry-over prevents the salts in the
boiler water from ever reaching the critical concentration so that the engine
is able to run indefinitely without priming.
The well water after complete softening, will contain in addition to the
original 4.5 grains, a further 11.9 grains of sodium sulphate, 1.6 grains
of sodium chloride and 3 grains of sodium hydroxide and sodium carbonate,
making a total of 21 grains per gallon. U sing this water the critical
concentration of 200 grains per gallon will be reached at 470 miles after
washing out. It is true to state that the success of water softening depends
upon the elimination of prim- ing. The simplest remedy, frequent changing
of the boiler water, is not recommended since it decreases to a very great
extent the engine's avail- ability. Three methods of preventing priming are
available. (1) Use of chemical anti-priming compositions; (2) intermittent
blowing down; and (3) continuous blowing down. Various compositions are available
for preventing priming in boilers. In a test one of these with fully softened
water it was found that the point at which priming commenced was reached
at 1,000 miles, whereas 500 miles was the limit without the composition.
The disadvan- tages of this method are that frequent water changes (every
1,000 miles) are still necessary and that careful and regular dosing of the
tender feed water with the composition is required. Inter- mittent blowing
down, which consists in removing a portion of the boiler water at frequent
intervals and replacing it with feed water is standard practice on American
railroads. American locomotives are fitted with one and sometimes two large
blow-off cocks which are operated either in the shed or at regular intervals,
usually every 20- 25 miles on the road. In the case of the largest engines
the volume of water blown down at the shed varies from 500-800 gallons; a
"blow" on the road lasts for 15-30 seconds and discharges 100-200 gallons.
The success of intermittent blowing down depends to a great extent on keeping
engines to the same working and in the hands of the same fewenginemen. The
normal washing out period on American railroads for engines fitted with blow
down and operating- on softened water is one month. Continuous blowing down
is the continuous discharge from the boiler of water at such a rate that
the concentration of sodium salts is kept just below that at which priming
occurs. This is effected by a valve which may be operated by hand, mechanically
or by steam pres- sure, so that blowing down takes place only when the engine
is working. The rate of discharge is controlled by a small orifice in the
valve and de- pends upon the class of engine and the amounts of sodium salts
in the feed waters. On the L.M.S. Railway this rate varies from 1 gallon
per minute for shunting tank engines to 2.7 gallons for ex- press passenger
engines and is equivalent to approximately 7 per cent. of the water consumption.
In order to minimise the loss of heat the blow down water may be passed through
a cooling coil in the tender before running to waste on the track. The valve
is bolted to a pad on the boiler back plate and takes boiler water from a
point 2 in. above the highest point of the crown of the firebox. The spring,
ball, seating and piston are of stainless steel. The controlling orifice
is in the cap which may be either mild or stainless steel. The cylinder at
the bottom of the valve is con- nected to the steam chest so that the opening
of the regulator brings the valve into operation automatically. A length
of armoured flexible hose connects the engine and tender pipes. Tank engines
on the L.M.S. Railway are not fitted with tender cooling coils, the blow
down water being discharged into the ashpan. The advantages of continuous
over intermittent blow down are that it is entirely automatic and removes
the minimum quantity of water from the boiler whilst 'keeping it free from
priming. The boiler wash-out mile- age will depend only on the amount of
scale-forming impurities which are being brought into the boiler by the feed
water. In the case of softened water containing a minimum of scale-forming
impurities the wash-out mileage may be extended to at least 5,000 miles,
this increasing to an ap- preciable extent the engine's availability.
Discussion: Verecker (Vereker?) (254) asked whether the LMS
used feed water trays and was informed that it did not: Verecker stated that
their use prevented corrosion. Selby (254-5) noted the cost of boiler repairs
in Scotland was far lower and that washing out could be at monthly intervals.
Selby and the author noted that on the Tilbury section trays had to be cleaned
every 7000 to 10,000 miles. In Scotland tubes lasted for five years and corrosion
was almost unknown.
T.H. Turner (222-6) noted the Institution has had
very few papers upon feed water: two in 1912 and one in 1924, and.in view
of the developments which have taken place in water treatment, it was time
for another. He agreed with the main findings of the Author: namely, soften
completely and the need for automatic blow down. That was his private opinion,
and not necessarily that of his chief [Gresley], who has, up to the present,
kept a very wary eye on all blow-down devices; but, has fitted his line with
more hot water washing out and filling up plants than have other railways,
he need not turn to blow down on the track so rapidly as others.Why had the
LMS Railway treated its prophets, Archbutt and Deeley, with so little honour:
because at the time of the amalgamation, the London and North Eastern Railway
had very many more softening plants than the London, Midland and Scottish.
Next, I should like to ask the Author why he takes a rather pessimistic
tone–and our President, Mr. Stanier, was rather halting in his attitude
in his Presidential Address–in regard to water treatment, when we see
the way in which it has gone ahead in the USA, in the Argentine and elsewhere,
and the strides that it has made in the last half-dozen years in Britain..
Considered that emphasis on priming and corrosion was excessive: they are
important and must be considel'ed, but more than half this Paper dealt with
priming and corrosion. It is incorrect to state that the success of
water-softening depends on the elimination of priming. We have priming, and
we always have had it. As a matter of fact, during this last summer it dropped
very considerably, although we were softening more than ever before, and
at the present time the figures show that it is less than at the corresponding
time last year. Priming is so much talked about that there is a tendency
to book time to priming, and therefore I am not sure how reliable the figures
are, but the running superintendents say that the engines are steaming more
easily, and the firemen like the water treatment and the total delays are
less than before. Perhaps it is only a matter of booking time, but of course
the management and the running superintendents will always try to avoid any
delays, and delays by priming will have to be avoided too.On the question
of definitions, it is a pity that we confuse priming and foaming, and are
not quite definite about it. We, the LNER, are trying to use "priming" for
that violent, sudden train-stopping ebullition, and "foaming" for the steady,
wet-water condition, the carry-over, which is hardly noticeable but which
is nevertheless from the economy point of view, equally undesirable. I think
tlult is a fair distinction between the two, but other people do not always
make it, and I suggest that we should try to keep to it.
We differ from the Author in thinking that we have proof that suspended
solids do play a part in the priming of locomotives. The senior chemist in
our water-treatment section is here to-night, and he may be able to give
actual cases of that, but so far as I have seen, we have evidence, that in
our engines, suspended solids do help priming. Of course, we know that the
dissolved solids must be taken into consideration, and that if we soften
and increase the dissolved solids we must expect more water changes. We shall
have very many fewer proper wash-outs, but we must have more water changes.
That water change may be done, as it is done on the London and North Eastern
Railway, with hot washing-out plants and quickly, because nearly always the
engine must go in for some mechanical work; but, if that is unnecessary,
by all means use automatic blow down. The Author refers to "continuous blowing
down" in the Paper, but I prefer the word "automatic" because we should not
call a thing continuous which is not in fact continuous, and which works
only when the regulator is opened.
I think is is quite wrong to say that partial softening is the cure
for priming-. I regard partial softening as a confession of defeat; it means
taking a wrong attitude in regard to the whole subject. We should have complete
softening, with increased water changes, and, if necessary, automatic blowing
down on the track. As a matter of fact, priming is not always increased when
you soften fully; we have had instances on our line, where, when we introduced
full softening, the priming decreased. It did not increase. Even the increased
amount of watcr change need not necessarily be uneconomical. At Doncaster,
for instance, the number of tubes saved in the sheds alone i.e., just the
materia1 cost of the tubes and not the labour-pay for the increased water
changes. '"
Turning to corrosion–If I go rapidly through these points, you will understand that, having been interested in this subject from the railway point of view for a number of years, the Author and I could go on chatting together for a very long time, but I must try to be as brief as possible under the heading- of corrosion, we are horrified by a set of tubes which the Author has exhibited, and it is rather suggested that a necessary result of softening is corrosion. In my viow, that is entirely wrong. In the very worst shed that we had for corrosion seven years ago, we were softening down to 8° or 10°; we cou]d not go beyond 8° because the priming was too bad. Several gentlemen who are here this evening will know that I am referring to Mexboro. Taking the years 1928 to 1930, and comparing them with the years from 1933 to the present time, during which latter period we have been softening right down by the addition of sodium aluminate to the lime and soda, and we find that corrosion has been very much decreased. The engines are lasting out in the sheds an average of ten months longer than before, which represents a 35 per cent gain in availability at the sheds before they must go to the shops. As a matter of fact, our water treatment section receive very few complaints with regard to corrosion, and when they trace them down they can nearly always be found to be due to the use of mixed waters or other waters' which are not softened at all. Where we have waters that are fully softened, the cases are so few that they may be regarded as freak cases, and are not worth mentioning.
The Author makes no special reference, in the section of his Paper headed "Corrosion," to Ph value and to the influence of magnesium chloride, both of which we regard as most important from the point of view of corrosion. Many of our waters contain magnesium-there is a region in the centre of the line where they are all high in magnesium and we find the addition of sodium aluminate to be of very definite benefit. We are rather surprised at the little use that the London, Midland and Scottish Railways have madc of it, despite the praise that the Author gives it in his Paper in the section headed' , Water Softening."
With regard to our practice, we base our practice on this conception, that the function of water treatment is to keep the sludge and scale out of the boilers, and therefore we cannot have any half measure's with it. If we have the conception of a balance sheet, we are spending the Company's money and we want something back for it. If we stop the softener for week-ends, and if we allow breakdowns-and electrical breakdowns and mechanical breakdowns keep cropping up with these plants-to stop the proper functioning of a good plant, then the balance sheet will rapidly be ruined. As a matter of fact, taking the present figures, our 31 plants are removing 950 tons of sludge and' 500 tons of hard scale per annum. That is what we may call temporary and permanent hardness, using the terms which, from the railway point of view, we shall understand better. These figures are based on the assumption that of the 9,000,000 tons of water that we treat in the plants, half is wasted; in taking these figures, I am assuming advisedly, from knowledge of a considerable number of plants, that half the water is never evaporated. If we assume that half the water that we soften is actually evaporated in the boilers, then on the sludge we are saving £14,000 and on the scale we are saving £44,000. Adding those two figures together, they come to well over twice the total cost of softening, including supervision by chemists and running' department staff as well.
Do not think that those figures are purely imaginary; they are not. We took ro8 engines of six different kinds in three different areas in order to build up the data upon which that estimate was made. I think we should bear in mind that that estimate. showed clearly that if we leave 5 grains of hardness in our waters we lose £24,000 of our possible saving. I think that is worth knowing. You may say, " Oh, but these are just figures, and we do not generally believe an accountant's figures and will not believe a chemist's figures." In view of that, I took the precaution yesterday of asking the local running superintendent and the local mechanical engineer whether it was safe to say that water treatment was doing any good. The reply was that the length of time in service had increased, the boilers were incomparably cleaner, less labour was now needed, the boilers were going into the shops in better condition, and three types of engines which normally had some of their tubes changed once or twice between shops now went from shop to shop without tube changes, and there were corresponding improvements in the copper stays.
I should like to take this opportunity of saying that any success which has been obtained-and I believe that we have obtained very considerable success-has been due to the gentleman whom I have mentioned, and his colleagues co-operating in such an intelligent and willing manner with the members of the water treatment section. That teamplay has helped enormously, and I feel that if i\he Author enjoys similar team-work on the L.M.S. they will very soon be setting us a high mark at which to aim.
To check up the views of the shed and the shops, I went to Mr. Thom and put the same question to him, and his reply was that the water treatment definitely was helping, and that I could say to anyone that he would defy them to say whether some of the Pacifics now coming off the Southern area, where we used to have the worst waters, had been running there or on the Scottish waters. That means a great deal, and anyone belonging to our Company will appreciate what it means, because Mr. Thom knows what a boiler is and has been in Scotland for many years, and the Scottish waters are regarded as perfect, whereas the Great Northern main line waters used to be definitely bad. ,
F.I. Bassett remarked that
he had presented Paper 8 on this subject nearly
twenty-five years ago-one of the earliest Papers read before the
Institution. It was, therefore, interesting to compare the
position of knowledge and practice to-day with what it was at that date.Water
treatment was now much more widely applied, although as regards the actual
technique of the lime-soda process, there had not been much advance. The
improvement had been mainly in the higher rate at which modern plants could
be worked and the increased efficiency of fi1ters and re-agent, mixing. The
base-exchange or " Permutit " process had been greatly extended in application
since the introduction of reliable synthetic material. The introduction of
sodium aluminate in the soda-ash treatment was a distinct
advance.
The problem of feed-water control on the Iraq railways was very much
more difficult than in this country, and the omission to provide for it when
the 350 miles of route was first opened between Basrah and Baghdad in 1920,
resulted in such frequent engine failures, that the service was greatly
disorganised. Softeners were then put in, but owing to the fluctuations in
the character of the water, it was necessary to work them under a system
of daily sampling and control from the Government Laboratory. After two or
three years the routine of softening had settJed down and failures on the
road became very infrequent, but the question of corrosion then emerged,
and in fact appeared to become more accentuated with the softened water.
He had given considerable study to this question since about 1926, both in
regard to boilers and to corrosion of pipelines buried in soil. Before discussing
it, however, he would venture a few remarks on the subject of
prining.
Priming, as the Author remarks, has never been strictly defined,
and the term "foaming" is used indiscriminately. In chemical engineering
practice it was recognised that steady or quiescent foaming would commonly
occur in any type of evaporator worked at as great a rate as a locomotive
boiler, and provision was therefore made to deal with the consequent"
entrainment" before the vapour passed to the condenser. He confirmed the
Author's observation that the tendency to foam, as measured by the" lift"
of the foaming surface, was mainly dependent on the proportion of soluble
salts-up to a certain point. Blow down-intermittent or continuous-was the
means of keeping down the concentration.
However, he did not think this general explanation could altogether
account for the sudden intense bursts of priming which occur without any
apparent reason. This was observed in some cases when the engine came on
a different water supply. There was reason to think that aggravated" priming"
of this kind, when the boiler conrlitions otherwise had not changed, was
due to introduction in the feed water of certain organic matter in small
traces, which were not usually looked for in analysis. Traces of soil humus,
for example, would cause priming. Most oils and fats brought about priming,
though it was remarkable that some three or four of them had a strong effect
in repressinK it, and the use of castor oil for this purpose was well-known.
,,It had been shown that certain scale containing traces of oily matter tended
to promote priming, and that this effect ceased when the oily matter was
removed. He thought there was need for further investigation on the generation
of steam bubbles from scaled heating surfaces of this kind.
I t might be that on certain types of surface it was difficult for
the bubbles to form, and the water ,became local1y superheated. Such effects
were often seen when liquids were boiled in glass flasks; although the rate
of heat supply was not altered, ebullition would slow down until it practically
ceased, and after a short interval of quiescence, an almost explosive liberation
of vapour would occur and continue for perhaps a minute or so in'violent
ebullition, notwithstanding the rapid temperature drop accompanying the
absorption of so much latent heat. This effect wasl called" bumping," and
cpuld be cured by the introduction of suitable angular or porous material
on which the bubbles could form regularly.
Manchester meeting: Ordinary General Meeting of the Manchester Centre was held in the building of the Literary and Philosophical Society, 36, George Street, Manchester, on Tuesday, 23 February 1937, at 19.00., the chair being taken by F. S. Cotton. 244-
J.S. Jones (245): Although much had been done in the last three years on water softening in this Country [Great Britain] there was still a long way to go before the question was thoroughly settled. He had recently had his attention drawn to a rather peculiar phenomenon. In the boiler of a shunting engine the corrosion usually took place in the top part of the boiler, whereas in the boiler of an engine working a train it usually took place at the bottom. Also in the case of the large shunting engines, particularly those used in “ hump ” shunting, the corrosion was noticed at the top of the boiler, yet in the same class of boiler used in an engine engaged upon ordinary train work, it was at the bottom. He had, he said, no solution to offer to this problem, but if there was one he would like to hear it.
Leeds Meeting on 23 March 1937. The Sixth Ordinary General Meeting of the North-Eastern Centre held at the Hotel Metropole, Leeds, at 7.15 p.m.; chair taken by F.H. Eggleshaw. 349-
Windle: The Author has shown
an American illustration of a boiler blowing down. They blow down mostly
from the foundation ring, whereas we blow from just above the surface of
the water. Is there any explanation of this? Author: The Americans fitted
their locomotives with blow down valves in order to overcome the priming
which arose after they had introduced water softening. They believe that
the presence of mud or insoluble matter in the boiler water is responsible
for priming and they placed their blow down valve below the foundation ring
in order to blow as much mud away as possible. In this Country that theory
is not so widely held and the reason why, on the L.M.S., the continuous blow
down valve is placed where it is, just above the crown of the firebox, is
really for safety. If, during the period that the engine is not being looked
after, the blow down should for any possible reason be opened, it will be
blowing down water until the water level is 2in. above the crowd of the firebox
and after that steam. If the valve were placed below the crown of the firebox,
the firebox would be damaged in the event of mismanagement.
Windle: What determines the size of thc blow down valve?
The Author: ‘The size of the boiler, the work it has to do, i.e. , the
normal rate of evaporation, and the amount of dissolved solids in the feed
water
Wilkins, J.H.A. (Paper No. 367)
The development of the locomotive turntable. 257-85. Disc.: 286-8.
Fifth Ordinary General Meeting ol the Session 1938-37 was held at
the Institution of Mechanical Engineers, London, on Wednesday, 27 January
1937, at 6 p.m., Mr. W.A. Agnew, Past- President, occupying the chair.
Turntables could be turned by manual effort, or by electric motors (at that
time the GWR had several and the LMS a few, or by vacuum (or by compressed
air as in Germany). The first vacuum-driven turntable was at King's Cross
(cited Rly Gaz., 1935 8 February and Engineering for 1936 31
July for experience after one year in service). A similar installation
at Camden on the LMS is also described.
Table shows total number of turntables in use on "English" railways in 1936:
LMS 395; LNER 326; GWR 118 (excluding a "few small tables"; and SR 88. Only
the GWR had a substantial number of unbalanced turntables (39). The table
is broken down by type of construction and by source of power.
In the American Railway Age for 18 November 1933, an article appeared on locomotive turntables dealing with a report which was presented before the 1933 Convention of the American Railway Engineering Association by Mr. J. M. Metcalf, Assistant Engineer of the Missouri-Kansas-Texas line. The Author listed the conclusions reached by this association at the subsequent discussion, which were later incorporated in their Proceedings. These are as follows:
The above conclusions are interesting and to a large extent are applicable to all types of turntables. Although the balanced type of turntable is to a certain extent losing favour, this type is still in common use, and for many years to come it will no doubt be used in this Country and abroad, particularly where smaller tables are required. The continuous girder type will no doubt gain favour, as well as the articulated type, both of which have many advantages, particularly for the large turntables now being built. Regarding the future, welding may be utilised in place of riveting for certain sections in a similar manner to that now in use in structural steel work. There is no doubt that ball thrust bearings for the centre pivot, and ball or roller journal bearings for the carrying wheels, arc now universal, and very few plain bearing tables arc likely to be built in the future.
Power operation is becoming more and more necessary and all tables over 60 feet in length, which are in frequent use, are likely to be fitted with mechanical or electrical assistance. In view of the possibility of increasing the length of turntables almost indefinitely, there would seem to be a chance of adopting even longer tables enabling two locomotives to be turned at once. This would, of course, only apply at busy sheds or terminals.
Graff-Baker, W.S. (Paper No. 368)
The retardation of trains. 290-305. Disc.: 305-17.
Sixth Ordinary General Meeting of Session 1936-37 and the Twenty-sixth
Annual General Meeting was held at the Institution of Mechanical Engineers,
London, on Wednesday, 24 February 1937, at 6 p:m., Mr. W.A. Agnew,
Past-President, occupying the chair.
Metadyne control system.
I feel that some apology is due to the Institution for the use of the elaborate
word “ retardation.” The Paper deals principally with the question
of friction braking, but friction braking is only one form of retardation
and it seems proper at least to refer to other forms before proceeding to
the consideration of the main subject. The problem of stopping a train is
that of dissipating its kinetic energy, which varies as the mass of the train
and the square of the speed. It is clearly impossible to dissipate the kinetic
energy of any object instantaneouslq. The rate of dissipation can be measured
in horse-power, kilowatts, or any other suitable unit, and whatever means
are employed for retarding a train must be essentially limited by the possibility
of dissipating the energy at a practicable rate. Broadly speaking, the methods
of retardation divide themselves into two categories :-- I. Those systems
in which the kinetic energy of the train is recoiered for use elsewhere or
for future use. 2 . Those systems in which the energy of the train is frittered
away and wasted by degradation into the form of heat. In the first category
come
Journal No. 137
Whitcombe, H.A. (Paper No. 369)
The history of the steam tram. 327-79. Discussion. 380-400.
Shown in error as 367.
Fourth Ordinary General Meeting of the Session 1936-7 was held at the Institution
of Mechanical Engineers on Wednesday, 6 January, 1937, at 6.0 p.m., Mr. O.
Bulleid (Vice-president) occupying the chair.
Holcroft (384-7): see
Holcroft. Paper contains a great deal of information, both as a general
historical survey and for listing which firms manufactured tramway locomotives
and tramcars, and which systems employed steam motive power. The latter included
Accrington Corporation; the Alford & Sutton Tramway; the Barrow-in-Furness
Tramway; the Birmingham & Aston Tramway co.; the Birmingham Central Tramway
Co.; Birmingham & Midland Tramways Ltd; Blackburn & Over Darwen Tramway
Co.; Blackburn Corporation Tramway Co.; Bradford Tramway and Omnibus Co.
Ltd.; Bradford and Shelf Tramway Co. Ltd; Brighton & District Tramway
Co. Ltd., Bristol Tramway Co. Ltd; Burnley & District Tramway Co.; Castlederg
& Victoria Bridge Tramway Co. Ltd; Cavehill and Whitewell Tramway Co.
Ltd; Coventry and District Tramway Co. Ltd; Dewsbury, Batley and Birstal
Tramway Co. Ltd; Drypool and Marfleet Tramway Co. Ltd. (Hull); Dublin &
Blessington Steam Tramway Co; Dublin Southern District Tramway Co. Ltd.:
Dudley & Stourbridge Tramway Co. Ltd; Dudley & Wolverhampton Tramways
Ltd; Dundee & District Tramway Co. Ltd; Edinburgh Street Tramways Co.
Ltd; Gateshead & District Tramways Co. Ltd; Giant's Causeway, Portrush
& Bush Valley Tramway Co. Ltd.. Mentions Loftus Perkins and Henry P.
Holt. An extensive precis of the paper was published in the Locomotive Mag.,
1937, 43, 23 and is incorporated below:
By way of introduction to the main subject of his paper,
Dr. Whitcombe gave a
general review of the earliest days of tramways. Primitive wood tramways
appear to have been in use as early as Tudor times, and by the middle of
the 17th century were well known in colliery districts, especially on the
banks of the Tyne. The first replacement of wood trams by cast iron rails
is recorded in 1767, at the Coalbrookdale Works
in Shropshire. This was followed by the adoption of iron rails in most of
the mining areas.
In 1809 a horse-railway was projected
between Gloucester and Cheltenham for the conveyance of passengers and goods.
Parliamentary sanction was obtained and it was duly opened in 1821. This
is said to have been the first passenger-conveying tramway in the world,
though there are grounds for believing it was antedated by the Swansea and
Mumbles Railway. A similar tramway was laid a few years later between
Stratford-on-Avon and Moreton-in-the-Marsh. Next
is a stone tramway laid in Commercial Road between Whitechapel and the East
India Dock in 1829; a curious reversion from iron to stone!
It was followed by a proposal in 1833 to construct a similar stone tramway
from London to Holyhead, which was to be operated by steam omnibuses, such
as at that time were being exploited with considerable promise of success
by Church, Gurney, Hancock and others.
The promoters, however, failed to obtain the necessary Act of Parliament
to carry out their enterprise, their Bill being thrown out by the vested
interests of the turnpike trusts.
It was not until 1852 that true tramways in their modern sense really made
their appearance, and here America carries the pioneer's palm, though it
was a Frenchman, Loubat, who was responsible for
the revival. Loubat laid a tramway from New York
to Haarlem, and returning to France, constructed a similar tramway in 1883,
from the Place de la Concord, Paris, to Plassy.
In this country a tramway was laid in Birkenhead in 1860, by Geo. Francis
Train of Philadelphia ; this remarkable man exemplified
to an excessive degree that type of American who is the traditional butt
of the caricaturist. There is little doubt he was a capable and enterprising
man, but courted the failure of his projects by his arrogance, and his colossal
impudence was displayed in the banquet he gave on the opening day of his
Birkenhead tramway: to this feast he invited all the crowned heads and
notabilities of Europe, including the Emperor Napoleon, the King of Prussia,
the Czar and the Prince Consort as well as prime ministers, bishops, scientists,
dukes, earls and noble lords ! It is not certain
whether he gave the Pope and the Emperor of China the opportunity of being
present, but he did not invite Queen Victoria ; not from any deference to
her Majesty, but probably because she was only a woman and women in those
days simply didn't count!
He published a brochure of this monstrous entertainment which is still extant
and contains full reports of his speech and the laudatory tributes he received
from his guests: he does not give a list of those who attended but he does
give a catalogue of all whom he invited!
In 1861, by permission of local authority, Train laid a tramway along Bayswater
Road between Marble Arch and Notting Hill Gate which survived only a few
months and in 1863 he made final effort in the Potteries. He boasted that
his Birkenhead Tramway was the first in the Old World and heralded the beginning
of a new and happy era in which he seems to shine as a sort of reborn Saint
George, although he must have been well aware that at that date trams had
been running in Paris for seven years, while on the opposite side of the
Mersey, actually perhaps in view of his terminus, he had been anticipated
by an English engineer, W. J. Curtis of London.
Two other pre-Parliamentary tramways must be mentioned, namely, John Howarth's
system laid in Salford in 1862 which survived several years, and the Portsmouth
tramways which anticipated Liverpool in 1868 but which did not receive
Parliamentary authority until 1870. In 1870 the North Metropolitan and the
London Tramways were opened, followed in 1871 by the London Street, Edinburgh
and Leeds, and, in 1882, by Birmingham, Glasgow, Belfast, Dublin, Plymouth,
Cardiff and Aberdeen.
Turning to the main subject of his paper, the Steam Tram, the lecturer referred
to its short life, for it really flourished only from about 1881-2 to 1901-2,
a rural system here and there lingering on till the last decade. The last
steam tramway in England had a dramatic end ; it
plied between Wolverton and Stony Stratford. It
joined the General Strike in 1926, and the General Strike was the end of
it!
Birmingham was wont to boast of its steam trams which with their ramifications
in the Black Country formed a continuous network of 67 route-miles operated
by about 200 locomotives and 180 cars—far and away the greatest steam
tramway system in the British Isles and probably in the world. In addition
to steam there were in Birmingham itself a few miles of horse, cable and
electric-battery tramways and in 1893 the over-head electric trolley system
was introduced in Walsall (incidentally this was the second electric trolley
tramway in England, the first having been opened in Leeds in 1891). The citizens
of Birmingham were proud of their steam trams and acclaimed them before all
others for efficiency, smooth and silent running and reliability.
Towards the end of their days they were accused of being dirty, smoky and
smelly—but only because, being doomed, they were neglected.
A steam tramway locomotive, when properly cared for, ran
smoothly and silently, was free from smell, showed neither steam nor smoke,
and needed no more be dirty or shabby than a horse, cable or electric
tram. It was economical too, and its shareholders were as delighted
with its performances as its passengers!
Nevertheless, at the close of the last century what we should now call a
great " stunt," was launched in, favour of electric
traction and the fickle man-in-the-street turned with scorn from his old
love to court the new ! Although this electric-mindedness spread throughout
the world, some countries escaped, notably Holland, Belgium and Italy, where
steam trams are still running as they ran over 50 years ago, giving satisfaction
and causing neither riot nor complaint. In Holland last summer the author
saw a little tram-engine, built by Henschel of
Cassel in 1881, still doing service after 55 years; but at long last the
steam trams of Holland are giving place, not to electric trams, but petrol
omnibuses—it is the decline of tramways, of of
steam traction, that is now sounding the knell of the steam tram in the Low
Countries. ,
In all the earliest steam trams the engine was placed in the car itself.
The first independent or dummy engine was made by Manning, Wardle and Co.
of Leeds who in 1866 made two for the Pernambuco Tramways. These were of
the locomotive type with horizontal boiler and two cylinders of 6 in. bore
and 12 in. stroke; the whole machine was enclosed in a cab and exhaust steam
was condensed by admission to a saddle tank. Seven of these engines were
built for Pernambuco between 1866 and 1870.
Very little of practical value appears to have been achieved before 1870,
and between 1870 and 1880 mechanical traction for tramways remained still
in its experimental stage both in America and in Europe. Several attempts
were made to produce fireless steam locomotives; these were ordinary locomotives
with the boiler and firebox replaced by a tank containing water superheated
under high pressure, which of course was charged by special plant at the
terminal stations. But steam did not have it all its own way and much ingenuity
was displayed by inventors who essayed with varying success to propel tramcars
by compressed air, coal gas, electric batteries, and so forth; the most
fantastic, perhaps, was the effort to drive trams by springs—clockwork
trains in fact; while the most absurd and dangerous was the use of
ammoniacal gas as the actual propelling force.
Such a car was actually constructed by Lamm, of
New Orleans, in 1871, though one would have thought that the rapid destruction
of the engine by the chemical action of the gas and the inevitable escape
of ammonia into the atmosphere would have been sufficiently patent to the
mind of the inventor to have condemned the idea long before it could have
been put into practice.
The first steam tram in England was designed by John Grantham in 1872, and,
as with the American pioneers, it was a combined engine-and-carriage. It
consisted of an ordinary four-wheeled double-deck car, in the centre of which
on either side was a boiler chamber, each of which contained a small vertical
boiler constructed on the Field system, 18 in. in diameter and 4 ft. 4 in.
high; the chambers were separated from one an-other by a passage open to
the interior of the car at either end, so that there was unobstructed
communication inside the car between the driver, conductor and passengers.
The engine was placed under the floor and consisted of two cylinders, 4 in.
diameter with a 10 in. stroke, acting on a single pair of driving wheels
of 30 in. dia. ; the car could be driven from either
platform.
Grantham who, unfortunately did not live to see the completion of his car,
entrusted the manufacture of the machinery to
Merryweather and Sons, having chosen this firm
because of its experience as fire-engineers in light engine construction;
the body work was built by the Oldbury Carriage and Wagon Works.
The car made trial trips in London and in 1876 was put into service on the
Wantage Tramway, but it was not a success. It was
reconstructed once or twice, the twin boilers were replaced by a single large
boiler by Shand Mason & Co., and, after many
vicissitudes and a long obscure history, it reappeared about 1903 for
experimental service on the Portsdown and
Horndean Tramway, and, when that tramway closed
down in 1934, it was still lying derelict in the company's yard.
In 1875, an Englishman, G. P. Harding, obtained a concession to work the
Southern Tramways of Paris by steam, and placed the order for the construction
of his rolling stock with Merryweather and
Sons ; but his machines were to be dummy locomotives,
not engine-and-carriage combinations. The first engine was delivered in Paris
in November 1875; it was a tiny little thing, 5 ft. 3 in. in length from
buffer to buffer, weighing only two tons ; it had
a small vertical boiler and horizontal cylinders, placed inside the frames,
of 5 in. diameter and a stroke of 9 in. The second engine, also having a
vertical boiler but rather larger cylinders (6 in.), was delivered early
in 1876; all succeeding engines were fitted with ordinary horizontal locomotive
boilers.
Altogether, between 1875 and 1877, Merryweather
and Sons supplied 46 locomotives for the Paris tramways. They were the first
steam trams in service in Europe and their success must be acknowledged since
their exploitation was followed by the adoption of
Merryweather engines in Germany and Spain in 1877
and in Holland and New Zealand in 1878.
In 1877 a
Merryweather engine was put into service at
Wantage where it either succeeded or ran in conjunction
with the Grantham car. But this was not the first steam dummy to be commissioned
in Great Britain, for in 1876 Henry Hughes, of Falcon Works, Loughborough,
patented an engine that ran for several months on the Leicester Tramways.
But the people of Leicester did not like it and it was transferred to Govan,
near Glasgow, where, with eight others built between 1877 and 1879, it worked
regularly till 1881, when the whole fleet was replaced by
Kitson engines.
Hughes also built an engine for Wantage and others
were put in service at Swansea, Bristol, Paris and Lille, but except the
Wantage engine, which continued to run until 1920,
none of them achieved much success. All these engines were of the saddle
tank type with inside cylinders from which exhaust steam passed to a tank
under the footplate where it was condensed by jets of cold water from the
saddle tank.
The practical perfection of the steam tramway locomotive was due to
Kitson and Co.. Although
it had built a combined steam car to the design of
W.R. Rowan for the Copenhagen
Tramways in 1876, this firm did not apply itself seriously to the making
of tram engines until 1878. Their first three engines were built that
year ; they had vertical boilers and two cylinders
of 6 in. dia. and 10 in. stroke placed outside the frame and inclined slightly
from the horizontal, motion being communicated by a modification of
Walschaerts' valve gear to four coupled wheels
of 2 ft. 0 in. diameter on a 4 ft. 6 in. base ; the regulator was operated
by a lever attached to the footplate which also controlled an automatic brake;
a governor was worked from the wheel axle. Each engine was completely encased
in a house or cab giving the appearance of a small tramcar, and the wheels,
gear and parts below the footplate were obscured by iron plates or
splashers. A special feature was the condensing
system which consisted of a series of copper tubes placed longitudinally
on the roof of the cab ; to these the exhaust steam was conducted from the
cylinders, was condensed by air-cooling and was returned to the water tank
whence it was again admitted to the boiler. This system of air condensation,
of course, modified in divers directions, became
universal for tram engines all over the world.
These three engines were constructed to no specific order ; they were definite
experiments de-signed to test practically the principles underlying the
requirements of a serviceable tramway locomotive. The results were the
abandonment of the vertical boiler for a horizontal one of ordinary locomotive
type and an increase in the size of the cylinders and wheels. In 1879 six
such modified machines were built and despatched to New Zealand, and no greater
tribute can be paid to the Kitson engine than to
record that five of these little locomotives are still doing yeoman service
at Christchurch in spite of their 58 years! In 1880 the Leeds Tramway Company
decided to adopt steam on certain sections of their under-taking, and
Kitsons were invited to supply the engines which
were constructed on lines exactly similar to the New Zealand engines except
that the longitudinal pipes forming the air condenser on the roof of the
cab were replaced by slightly arched transverse tubes—a great improvement
on the earlier arrangement. The Leeds engine remained the type or standard
engine until 1884, when many improvements were introduced, of which the most
important was a considerable increase in the size of the boiler and firebox
; other minor improvements affecting the dome, sanding, condensing and so
on were added from time to time, but the general principles of construction
remained the same from 1878 to 1901 when the last
Kitson tramway engine, the last British tramway
engine to be made, was built for the Portstewart
tramway in Northern Ireland.
The track of this line became so bad that at the end of 1925 the Northern
Counties Committee of the L.M.S.R., the owners, condemned it and removed
the rails in 1926, replacing the trams by omnibuses. One of the engines was
offered to the South Kensington Museum to be preserved, but the authorities
declined it.
Kitsons built over 300 of these engines, mostly
for tramways at home, a few going to the dominions and abroad.
A rather remarkable tramway engine was patented by William Wilkinson, who
had a foundry at Wigan. In 1881 he arranged with the Wigan Tramway to experiment
with a locomotive he had designed. It was a vertical engine with a vertical
boiler; the cylinders were of small bore and stroke (6 in. by 7 in.) and
acted upon a crank shaft through which motion was communicated to the
four-coupled wheels by gearing. Exhaust steam was not condensed but was
super-heated in a contrivance in the firebox whence it escaped to the atmosphere
through the chimney. It had several other special features, was small and
light, and on its introduction very favourable anticipations of its future
were entertained by many engineers. It was adopted
at Wigan and attracted the attention of the promoters of the Manchester,
Bury, Rochdale and Oldham Tramway Co. (the second largest steam tramway
undertaking in the country), the South Staffordshire Co. and the Huddersfield
Corporation.
The early popularity and demand for the engine out-stripped the productive
facilities of the patentee who was constrained to place a proportion of orders
with three other firms of engineers, namely:—Thomas Green & Son
of Leeds; Black, Hawthorn & Co., of Gateshead, and Beyer, Peacock &
Co., of Manchester. The engine, especially in the hands of Beyer, Peacock
& Co. proved a very serviceable machine, but it failed to compete with
any success with the Kitson, and its manufacture,
after reaching 200 engines, practically ceased in 1886. The finest of the
series was the last consignment by Beyer, Peacock to the Manchester, Bury,
Rochdale and Oldham Co. Built in 1886, this consignment consisted of 24 engines
with cylinders of 72 in. by 11 in., the most important feature, however,
being the replacement of the superheaters by air-cooled
roof condensers of the Kitson type. They were
magnificent engines and continued to run with the fullest satisfaction until
the electrification of the system was completed in 1905.
Poole, A.J. (Paper 352)
Locomotive boiler proportions and design (with particular reference to Indian
practice). 403-9 (Summary). Disc.: 409-
This refers back to original presentation (Vol. 26 Journal No. 131).
Discussion is noteworthy in that the President (W.A. Stanier) was
present in Delhi and concluded the discussion. Before that L.N. Flatt noted
a few years back he was fortunate enough to be allowed to ride on one of
the fast trains at home to Doncaster with a heavy load, and was astounded
to see the ease with which steam was maintained. Almost from tbe start to
finish there was just a whisper of steam at the safety valve at periodic
intervals and the fireman did everything which, according to those advocating
mechanically operated fire doors, was wrong in practice. From start to finish
he never threw a shovel full of coal. The coal was piled in the fire
door which was never shut, and as Mr. Stanier has said, was allowed
to feed itself both forwards and sideways. The whole trip was a lesson in
the extremely efficient results obtained from the boilers of these locomotives
on the London and North-Eastern Railway.
The President (Stanier) (420-2) could at any rate accept some of the
statements made in the Paper with greater confidence than some of the claims
made regarding American practice referred to by Mr. Case. Mr. Case also referred
to fire grates having an air space of 13.5 per cent. of the grate area. We
in England are now experimenting with an air space of 55 per cent. grate
area, and we are hoping to get better results than we have had with an air
space of about 48 per cent. grate area. I think the quality of coal used
is important, and I am rather surprised at the small air space tried out
here. Mr. Case also referred to steel fireboxes. They are fitted in the States
in wide firebox boilers, and are extraordinarily successful in the Eastern
States of America.
Mr. Wrench also referred to the question of copper fireboxes and steel fireboxes. I do not think his experiment justified condemning steel fireboxes. My experience is that if you put steel fireboxes in narrow type fireboxes, trouble is to be expected, but if steel fireboxes are fitted to wide type fireboxes, they give satisfactory service. A particular example that may be of some interest is the case of the standard War Department locomotives used in France during the war, and used after the war on English railways. A good number of these, R.O.D. engines, some 250, designed by the Great Central Railway and used in France during the war were fitted with steel fireboxes. Later, after the war, when used on English railways, their fireboxes had to be replaced by copper fireboxes because of the plates cracking between stays. It seems to me that when steel fireboxes are put in narrow firebox boilers, you get trouble of that kind. Mr. Wrench also referred to the question of steel stays. Well, I have had many years' experience of steel stays. The wide firebox boilers on the L.M. & S. Rly. are fitted with steel stays except in certain areas. We did not use flexible stays, as such stays are commonly called, that have special provision for allowing certain movement, but used flexible steel stays–a stay ¾in. diameter, but flexible in itself.
Mr. Sindhu referred to the question of steam pressures of locomotive boilers, and the fact that stationary boilers have steam pressures of 450lbs. per sq. inch, and 750 degrees of superheat. Locomotive boilers with pressures higher than this have been built, but it must be remembered that they are experimental boilers; no repeat orders have been given for boilers such as the Swiss and German locomotives fitted with high pressure boilers. One is making history slowly with regard to high pressure locomotive boilers. The usual high pressure locomotive boiler pressure is 250lbs. per square inch. Mr. Sindhu also refers to the question of weig'ht in locomotive type boilers.One type of locomotive we are getting out in England keeps the boiler weight down considerably by the extensive use of high tensile steels for the boiler plates. With regard to Mr. Sindhu's remarks on water tube boi1ers, it must be realised that with a water tube boiler on a locomotive, it is very difficu1t to keep the boiler high enough to get circulation a1wavs in the same direction. Sometimes when steaming hard, the direction of circulation is completely reversed in a water tube locomotive boiler. Mr. Sindhu also, refers to the question of water softening, and its effect on the maintenance of the locomotive boiler. It is very little use putting down a few isolated water softening plants if locomotives are also to draw water from stations not provided with water softening plants. On the L. M. & S. Rly. we have installed water softening plants. for the whole of the North-Western Section. I am afraid it is too early for me to give you figures relating to savings effected on maintenance. We have 20 locomotives working on a particular section, where water softening plants are installed, and some of these locomotives have run 10,000 miles between washing outs. Of course, in some parts of Scotland, where the water is remarkably soft, very little boiler trouble is experienced and installing water softening plants in such districts is hardly justified.
Rajangam, Sri (Paper No. 370).
Some factors contributing to derailments of railway rolling stock. 427-46.
Discussion. 446-8.
Shown in error as Paper 368.
Branch Meeting of the Southern Section of the Indian and Eastern Centre of
the Institution was held on Saturday, 11th July, 1936, at the Railway Institute,
Perambur, Mr. E. L. Roberts, Chairman of the Branch, occupying the chair.
Journal No. 138
President of the Institution, Session, 1937/38: Lieutenant-Colonel
Francis Richard Collins, D.S.O. 461.
See biographical
material.
Noble, E.C. (Paper No. 371)
The economics of locomotive engineering. 478- 99. Disc.: 499-514.
Fourth Quarterly Meeting of the 1936 Session of the South-American
Centre held Friday, 18 December 1936, at Ibicuy, the chair being occupied
by Mr. O. Steven, Chairman of the Centre. The programme of the members, by
the kind invitation of Mr. John Wilson, General Manager, included a visit
to the Entre Rios Railway Ferry, which runs between Ibicuy, Zarate and Puerto,
Buenos Ayres, the stock consisting of five boats, three with four tracks
and two with three tracks.
MacAulay, D. (Paper No. 372)
Some notes on the mechanical aspect of working steam-operated suburban services
with particular reference to the Eastern Bengal Railway locals around Calcutta.
517-40. Disc.: 540-51.
Ordinary General Meeting of the Indian and Eastern Centre (Eastern
Branch) was held at the Great Eastern Hotel, Calcutta, on the 26 June 1936,
at 6.30 p.m., Mr. L. N. Flatt, Chairman of the Centre, occupying the chair.
The Chairman (L.N. Flatt) referred to the opating practices adopted at Liverpool
Street station in London: It will be noted that the Author refers to the
intensive service entering Liverpool Street Station and states that the fireman
uncouples on arrival and then takes water. Having worked into Liverpool Street
when firing, I can assure him that I have suffered quite good tempercd but,
nevertheless, caustic criticism from my driver when doing these things in
the order quoted by the Author. The time allowed at Liverpool Street is so
short that the first essential is to get the water column into the tank opening
and open the cock, after which the engine can be uncoupled. It is only in
this way that the full quantity of water can be, obtained before having to
follow down the outgoing train to enter the refuge siding. I mention this
point as it emphasises how very important the odd few seconds are, when working
intensified suburban services.
Meeting in Bombay 27 August 1936: paper read by D. Williams
Discussion: G. Da Costa: (548) The Author has chosen a very interesting
subject. His comparison ot the timings ok the steam operated suburban trains
of the Eastern Bengal Kailway and those of the electric traction units on
the Great Indian Peninsula Railway suburban service indicates that there
is little scope for further acceleration of the E.B. suburban traixis. I
deduce from this, that the 2-6-2 ST class locomotives are an excellent locomotive
for the service. They are as powerful at low speeds as the SGS 0-6-0 locomotives
and superior at high speeds by virtue of their larger coupled wheels. Tcsts
on SGS locomotives on suburban trains of 10 bogies (373 tons) have shown
that they accelerate to 10 m.p.h. in 27 secs., 30 m.p.h. in 2 mins. 4 secs.
and 50 m.p.h. in less than 4 minutes. The ST class is now expected to haul
only 160 to 224 tons, but, as they can accelerate as well as the SGS, it
is fairly evident they can cope with the fastest Eastern Bengal suburban
trains even when the loads rise to 10 bogies. ’They may, therefore,
be expected to continue to give good results for several years. It is not
quite clear why the Author’s ideal locomotive should differ so widely
from the ST class. I find that if he requires his ideal locomotives to give
as good a performance as the ST (or SGS) locomotives they would have to work
to a boiler pressure of about z651bs./sq. inch. If the pressure is zIoIbs./sq.
inch, the cylinders should be at least 16in. in diameter. At best, on a
semi-pooled suburban locomotive, the third cylinder represents just so much
more maintenance. I think the author would have done much better by sticking
to the ST design with two outside cylinders only. The Author condemns the
multiple valve regulator as unsuitable for locomotives fed with water w-ith
a high degree of salinity. He does not seetn to consider poppet valves at
a disadvantage on the same ground. When priming occurs with bad water, a
poppet valve often seizes and is therefore a potential cause of failure.
Tests have shown that the oscillating cam type of valve gear on SGC locomotives
has no appreciable advantage in acceleration or fuel economy over a piston
valve operated by the same link motion. The Author’s suggestion that
the OC type SGS locomotive4 return a bettcr acceleration but a worse fuel
consumption than the corresponding piston valve locomotives is inconsistent.
If an engine uses more coal per h.p. hr., it is because it uses more steam
per h.p. hr. (the boilers being identical), and if it uses more steam, it
must develop a lower power from a given boiler, hence it should be poorer
in acceleration. Except on grounds of maintenance, there is nothing to choose
between the piston valve SGS and its OC poppet valve conversion. Both locomotives
do well with a 4qin. blast orifice.
D. Williams (549) found two things of particular interest in the Paper:
the first is that no less than eight types are represented among the 47 engines
which the Eastern Bengal Railway utilises for its passenger suburban services
around Calcutta. It must be rather inconvenient and expensive to have to
carry renewal parts for such a variety of iocomotives, totally only 47 in
all, but the Author of the Paper is evidently not dismayed, for he proposes
a ninth type entirely different from the other eight. The second matter is
that the Author of the Paper is evidently not satisfied in his own mind whether
oil or grease is preferable for axlebox lubrication. Much, of course, depends
on the set of conditions which are encountered, and, in hot and dusty countries
like India, it seems to be generally considered nowadays that grease is a
better all round lubricant than oil for axleboxes; on the other hand, the
Author is evidently very pleased with what his railway describes as the
‘‘ Victorian box, ” which, being hermetically sealed, defeats
one of the most serious objections to oillubricated axleboxes in this country,
namely, the mixing of oil and grit to form an abrasive compound, rather than
a lubricant.
It is understood that no less eminent a railway chief mechanical engineer
than Sir Nigel Gresley is firmly opposed to grease as a steam locomotive
lubricant, anyway, he has stuck to oil for his very remarkable locomotives
of the “Silver Link” and “ Cock o’ the North ” types,
but the London and North Eastern Railway locomotives do not have to work
in sand and dust storms half the time they are in service, neither do their
axleboxes suffer an afternoon sun beating on them at 140’F. There is
no doubt at all, in my own mind, that a good quality lubricating oil (not
the cheapest in the market, under fierce competition) is a better lubricant
than grease for all fast running machinery, but unhappily oil is much more
liable to contamination by grit and water than is grease; consequently, for
“ rough and tumble ” conditions, in a hot and dusty climate, grease
has certainly important advantages over oil. I am satisfied, by long experience,
that most of the trouble in overheated oil-lubricated axleboxes is due to
dust and grit finding its way into the boxes. The “ Victorian ”
hermetically sealed axlebox therefore appeals to me, the only thing I should
be afraid of, being a driver’s anxiety as to whether there was sufficient
oil in the box, causing him to open it out in some way or other to see for
himsell‘ and thereby destroying the n-hole purpose of this type of box.
Finally, I note with interest that the Author favours partial pooling,”
which, on the G.I.P. Railway, we describe as “ partner-crewing ”
; evidently, like most oi us, he is riot quite satisfied that indiscriminate
pooling will definitely facilitate intensive locomotive usage. Ho\\ much
money and care is expended on locomotive maintenance in running sheds, one
has always to cope with human frailty, in the form of drivers whose attitude
in thc, matter of “ nursing ” an overheated bearing, for example,
is that it will complete his part of the round turn without causing an engine
failure and that he is unlikely to be burdened with this particular engine
again before the trouble has been rectified. With ‘‘
partner-rrewing,” the two drivers’ interest in their engine is
sustained, and, provided conditions make it possible (or No. I driver to
get sufficient but not excessive rest at his home station while No. 2 driver
is out with the engine, it will surely be found that the idle h i e of their
engine in shed is only sufficient for maintenance requirements.
Scott, J.I. (Paper No. 373)
Roller bearings. 552-9. Disc.: 559-61. 7 diagrs.
Third Ordinary General Meeting of the Scottish Centre was held in
the Societies Room, Royal Technical College, on Thursday, 17 December 1936,
at 7.30 p.m., the Chair being taken by Mr. G. A. Musgrave: also next two
papers.
Discussion: K.R.M. Cameron (560-1): Perhaps the
most important benefit from the roller bearing is the reduction of hot boxes.
While the reduction in starting resistance is definitely considerable, the
rolling resistance is not very much superior to a well finished and lubricated
white metal bearing. 1 believe the old Midland Railway carried out tests
some years ago which demonstrated this point. The hot axlebox question is
one which occupies a major place in the locomotive engineer’s thoughts,
and in this field the roller bearing is likely to show most advantages over
the ordinary bearing. Anything which can reduce the likelihood of a hot bearing
is welcome these days, as I have experience of hot boxes which have done
as much as £150 worth of damage in one single case, and this multiplied
several times in a year’s working among a thousand or so locomotives
will soon make a substantial hole in the year’s profits. Stanier’s
new turbine locomotive for the L.M.S. has roller bearings throughout, and
I understand that in a good many thousand miles the bearings have not given
the slightest trouble. A well-tried example of the use of roller bearings
for locomotives is for the return crank on Walschaerts valve geared engines,
a practice which has been standard on the L.N.E. Railway for some 15 years
now, and is now being adopted for the larger L.M.S. locomotives. A specialised
form of roller bearing is the needle roller type for bearings having only
a partial rotatory motion, and these have been successfully applied to the
motion of the later L.M.S. 4-6-2 engines. Unquestionably roller bearings
represent a step in the right direction, but they will require to demonstrate
very substantial savings before the railway companies adopt them generally,
on account of their relatively high cost.
Stewart-Fergusson, I.D. (Paper No. 374)
New methods of locomotive cylinder production. 562-70. Disc.: 570-2. 7 illus.,
2 diagrs.
New process in which the whole cylinder was made of cores. For this
purpose sharp sand containing rather more than the usual amount of binding
oil was used. Before starting to make the cores, a shallow box, the size
of the moulding box, was filled with sand, levelled off, and baked. This
forms a table or foundation for the whole mould. The bottom core is the first
and largest one to be made. The core box was filled with the sand and the
core was strongly reinforced with bars of iron and sprigs. These are here
to give strength to the core, but, what is more important, to enable it to
be lifted once it has been baked.
Advantages of new moulding process:
1. Provided that several cylinders of the one class were being produced,
it was quicker than by the usual method and consequently cheaper.
(2) In the event of a cylinder bcing required in a desperate hurry, it was
possible to have as many as a dozen men working at once making thc cores
without interfering with each other. This would be quite impossible on the
ordinary mould where only two men could work at once.
(3) The main advantage, however, was that very little skilled labour was
needed to make a cylinder by this method, and an apprentice with a limited
amount of foundry experience could make one of these cylinders unaided.
Turner, James (Paper No. 375)
The locomotive boiler. 573-9.
Read 17 December 1936, in Glasgow. A graduate paper.
The most important rule in boiler design is to make the boiler as large as
loading gauge clearances and permissible axle loading will allow. Many
locomotives have been designed which have been definitely "under-boilered",
but “over-boilering” is an unknown complaint. For a particular
engine, it can be taken that the larger the boiler, particularly as regards
grate area, firebox volume and tube cross-sectional area, the lower will
be the fuel costs, or in other words, the more efficient will the boiler
be. Larger boilers, too, invariably reduce maintenance costs.
Some average boiler dimensions were appended. The column headed "Standard
British Boiler" is composed of figures obtained by averaging the particular
value for about a dozen express locomotives of the LMSR., LNER. and a few
of the Southern Railway. The Great Western Railway has been put in a separate
column to show the difference in grate area, firebox heating surface and
superheater heating surface. The typical G.W.R. narrow deep firebox was reflected
in the difference between its grate area and heating surface compared with
what might be called the " Standard British Boiler. '' The difference between
their respective superheater heating surfaces is worthy of comment.
Collins, F.R.
Presidential Address. 586-625.
Richly illustrated: main theme was effects of gauge. Began with WW1
2ft gauge 10 ton capacity bogie wagon. Noted that he could remember the GWR
broad gauge conversion. Noted the multiplicity of gauges in India and Australia
and implied thatt high capacity could be achieved on the standard gauge.
Illustrated this by a Virginian Railways gondola car which ran on six-wheel
bogies and had an axle load of 24 tons. Coal trains of 10,000 tons could
be operated. The LNER operated 50 ton capacity bogie wagons. Most of the
Address related to freight, but modern passenger stock was also
considered.
Wall, H. (Paper No. 376)
Iron and copper pipe working. 626-40. Disc.: 640-2.
Seventh Ordinary General Meeting of the Western Branch of the Indian
and Eastern Centre held in Bombay on 17 December 1935: A. Richardson occupying
the Chair.
Scott, J.S. (Paper No. 377)
The lining-up of locomotive frames, cylinders and axleboxes. 643-66. Disc.:
666-76.
Seventh Ordinary General Meeting of the Session 1936-37 held at
Institution of Mechanical Engineers, London, on Wednesday, 24 March 1937,
at 6 p.m.. W.A. Stanier, President of the Institution, occupying the chair.
The opto-mechanical method of aligning frames using a telescope was covered
on p. 657 et seq. H. Chambers (666) was a little disappointed to see,
on the form issued to the shops for repairs to axleboxes, with regard to
the dimensions of the journal, fillets on the left-hand journal of ¾in.
and 1in. and on the same axle, but on the other side, 7/8in. and 1in., and
I hope, though the author said that the shops had no need for a drawing,
that the foregoing is due to an error in the dimensions on the
form.
I was struck, too, by the Author's remark that on axles where collars
were provided very great care was taken to give a clearance on the collar
side. My expeience was that the inside collar was provided to take a share
of the lateral thrust of the axlebox and so reduce the pressure on the opposite
wheel boss. I agree that with modern locomot!ves, with a large wheel boss,
collars are not being provided on the journals of the axles.
The President has already said that the mechanical method of setting
out the frames is that used on the London Midland & Scottish Railway,
and I have no doubt that a similar method is in general use in this Country.
With regard to the alternative optical method, I am inclined to say that
it is a complicated system, and I should like to ask the Author what is the
time required to set up the Zeiss optical apparatus as compared with the
mechanical system? 1 would also point out that this question is affected
by the fact that at Crewe and at other large works the belt system is employed;
would the Author recommend the optical system, bearing in mind the engine
is taken from stand to stand, as the repairs progress?
J. Clayton (668-9) Like other speakers, I have been
much interested in this very practical Paper. It is good to find that someone
does believe it is still worth while taking meticulous care over the poor
old locomotive. The old idea of a straight-edge and a piece of string of
varying thickness may have been regarded as satisfactory in the past, but
to-day, as the Author shows, endeavours are being made to apply the use of
instruments of precision now available to replace old methods. I should like
to see more of this care exoended on locomotives that go in for repairs,
not only at the works, but also in the running sheds. This Paper is a very
opportune one, and it should be of immense use to those on our railways in
this Country and also to railways abroad.
On the question of collars on axles, our experience on the Southern Railway
is that they can be dispensed with provided care is taken to ensure that
wheel face surfaces are ample in all cases
Meeting in Glasgow, 18 March 1937 672.
The Annual General Meeting of the Scottish Centre was held in the
Societies rooms, in the Royal Technical College, at 7.30 p.m. Mr. Robertson,
Vice-chairman, occupied the Chair, in the unavoidable absence of Mr. G. M.
Musgrave.
I.D. Stewart-Fergusson (673) When going through
the German repair shops I made a point of noticing how they lined and squared
their frames. The method of using the string and square was the only one
we saw being used, there being no sign of the optical method. This bore out
my contention that the optical method, though of possible value in buildings,
is far too accurate for repair work. I would like to have the Author’s
opinion on the placing of engine jacks. I have seen an engine having its
horn gap sizes taken while the boiler and cylinders were out, and unless
the jacks are placed in a particular position there will be a considerable
change in the gap size when the weight comes on the fore end. So, with a
view to avoiding this, I would like to know if any system has been worked
out for the placing of jacks, so that the resultant frame stresses would
correspond as nearly as possible to those met with in running practice. My
next question concerns the welding of frames. It is common knowledge that
there is a permanent elongation in a plate that has been welded. What effect
is this going to have on an engine that has, say, two welded fractures on
the one frame plate? If one was above the leading gap and the other above
the trailing gap, then the engine would be very decidedly thrown off the
square and the position of the datum points would be altered with respect
to each other. Would the cylinders, motion plate and frame stays have to
be refitted ? The
Webber, A.F. (Paper No. 378).
The proportions of locomotive boilers. 688-725. Disc.: 726-63. 8 diagrs.,
8 tables. Bibliog.
Second Ordinary General Meeting of the Session, 1937-38, was held
at the Institution of Mechanical Engineers, on Wednesday, 27 October, 1937,
at 18.00:. F. R. Collins, President, in the chair.
Abstract reproduced from Loco. Rly.
Carr. Wagon Rev., 1937, 43, 343-4. Mentioning the high standard
of performance of the Stephenson locomotive boiler, comparison was made with
stationary boiler practice. The essentials of effective boiler design are
distinguishing features of the Stephenson boiler, in the completely water-cooled
combustion chamber, efficient convective heating surface, and comparatively
strong draught, giving high gas speeds, and in its immediate effect the steam
locomotive appeared complete. It is this direct-acting reciprocating steam
locomotive, altered only in propor- tions, especially as far as the boiler
is concerned, which is to-day still responsible for moving the bulk of the
world's land transport. Reviewing the developments in stationary boiler practice,
the steam output of a Lancashire boiler has been more than doubled in recent
years, but these results are completely eclipsed by the astonishing combina-
tion of high output and high efficiency of the modern locomotive boiler,
even more astonishing when attention is given to the restricted dimensions
and the enforced absence of economisers and pre-heaters on which the stationary
boiler so largely depends.
The development of really high-speed express trains of limited weight accompanied
by a general acceleration of heavy main line trains running to more ordinary
schedules may result in greater demands on the locomotives, The steaming
capacity is severely tested when time is being kept (or regained) on long
adverse gradients; the importance of cylinder design is not quite so paramount
as where extremely high speeds of well over 90 m.p.h. have to be attained.
Therefore the maximum possibilities of the steam locomotive must be considered
seriously, and in the author's opinion the boiler comes first. Emphasis is
laid on the value of a "free-steam- ing" boiler to the load-hauling capacity
of the locomotive, even at the expense of a slight loss of thermal efficiency.
It will be realised that a modification to a given engine which will enable
it to do the same work for 10 per cent. less fuel, is less valuable than
a modification which will enable it to do 10 per cent. more work for the
same fuel consumption. In the one case a certain item in the overall cost
of transport (admittedly an important item) has been reduced, in the other
case, not only is the fuel-power conversion more efficient, but the locomotive
has become a very much more valuable unit of the railway service. This is
confirmed by the frequent instances in which a class of locomotive has been
rebuilt with larger boilers and thereby transformed from et condition where
the performance has been disap- pointing in. relation to the weight, cost,
and gene- ral dimensions of the machines, to a condition in which the engines
have proved valuable and effective units. Even where the performance in the
original condition has been quite good, the provision of a larger boiler
has often enhanced greatly the effective transport value of the locomotive.
An example of this (though not strictly a case of re-boilering existing
locomotives) is given by the comparison between the small and large boilered
Great Northern Atlantics. Though both classes are almost identical, apart
from the very different boilers, the earlier engines have been for long relegated
to secondary duties, while the larger engmes have only just been displaced
from working the 290-ton Pullman trains on schedules demanding a very high
standard of locomotive performance. Such locomotives are, from the operating
point of view, of infinitely greater value than the earlier " Atlantics,"
and these considerations should be kept in view when discussing boiler
design.
. When it comes to getting the maximum possible output from the locomotive,
this is essentially a boiler problem. Since the multi-cylindered locomotive
has been generally adopted for high powered machines there is no difficulty
in fitting cylinders large enough to utilise efficiently (at not too late
a cut-off) all the steam that the boiler can deliver. The effect of front
end design on maximum output is chiefly that the more efficiently the steam
is utilised the greater effective output can be produced from a given maximum
evaporation. The design of the boiler is far more stringently restricted
by space limitations, and it is for this reason the author considered boiler
design to be the key to the future development of the steam locomotive. He
is inclined to believe also that the recent developments in front end de-
sign have not been quite paralleled by progress in boiler design.
The real difficulty is to separate free steaming from coal eating. The boiler
must be capable of burning coal at a high rate. When so doing, the coal must
be completely and efficiently burnt. When this is done, the boiler heating
surface must be capable of transmitting a high proportion of the resultant
heat to the boiler water to form steam.
An arrangement of small bore boiler tubes may give a high thermal efficiency,
but given vacuum in the smokebox, will not give sufficient draught in the
firebox for the combustion of coal at an adequate rate. It will be necessary
to sharpen the blast by restricting the exhaust nozzle or by work- ing with
a partly closed regulator and a late cut-off, giving a high cylinder release
pressure. Neither expedient is economical, but the real weakness of the design
is the inability to produce enough steam for heavy load hauling.
The tube system must be so designed that it will not absorb too much of the
smokebox vacuum for propelling the gases along the tubes. The firebox grate
area is also closely associated with good steaming qualities, since a high
rate of finng per sq. ft. of grate area requires a greater draught in the
firebox to induce the enormous volumes of air through the firebed. The grate
area also affects the boiler efficiency very much, since, one of the most
serious sources of heat loss is the loss of solid unburnt fuel which increases
rapidly at high ratings. Regarding the importance of the area through the
tubes T. Grime (Steam Locomotive Performance,
Journal Volume 16 No. 75, p. 604 Paper
200). stated that the maximum evaporation depends solely on this factor,
and giving as a maximum figure 7,000 lb of steam per hour per sq. ft. of
tube area, while E.W. Selby (Practical Points in Locomotive Design,
Journal Volume 14 No. 66, p. 493 Paper
168) suggests that the area through the tubes should not be less than
one-fifth of the grate area. It would seem difficult to maintain the last
mentioned ratio with the large grates of modern "Pacific" locomotives, and
in any case the area through the tubes is not the only criterion of the
resistance to the gas flow. The tube length will obviously affect this factor,
and as locomotives have been designed in this country within the last few
years with tubes as short as 12 ft. 4 in. and as long as 20 ft. 9 in. the
effect of tube length cannot be neglected. Furthermore, a given total area
through the tubes will afford freer flow to the gases if it is pro- vided
by large bore tubes than by a larger number of smaller tubes. It would seem
as though there .is little help to be gained from the simpler arithmetical
ratios of boiler heating surface to tractive effort, or area through tubes
to grate area, and the author has attempted to develop a method of analysing
and comparing boiler proportions and performance which, based on experimental
results, may be expected to establish a rational order. The method adopted
is to calculate the boiler output, efficiency and draught requirements over
a range of firing rates by means of the Lawford Fry formulae, based on results
from the American testing plants. This method of analysis has been applied
to 22 British express locomotives of widely varying dates, types and sizes,
and it is suggested that the resultant curves for boiler out- put plotted
against draught requirements dis- tinguish clearly between boilers known
to have good steaming qualities and those of indifferent merit in this respect.
It is even suggested that a formula connecting output with draught (when
calculated in accordance with the methods suggested by the author) can be
constructed to indicate whether a boiler design is or is not likely to be
free-steaming in service. Brief consideration was also given to the effect
of "over-cylindering" of locomotives and to some possibilities of increasing
boiler output without sacrifice of efficiency. .
Analysis of boiler design on a comparative basis: included LNWR Precedent,
Greater Britain, CR Dunalastair, LNWR Precursor and George the Fifth, GNR
C1 Atlantics (superheated and sarurated), LSWR D15 and T14, D11 (Director
class), Claughton, B3 (Lord Faringdon), King Arthur, SR N15X (Remembrance)
class, Patriot 5XP, V (Schools), Castle, A3 Pacific, A4 Pacific, 7P Princess
Royal, 7P Coronation and LNER P2 class in relation to 5 theoretical firing
rates (40 to 120), smokebox temperature, heat output and efficiency..
The President, F.R. Collins, (page 726) opened the discussion: he had been
a Webb pupil: and noticed that the design of the Greater Britain boiler
was received with a certain amount of amusement. His impression of what had
been referred to as a combustion chamber, placed in the middle of the barrel,
was not so much a combustion chamber, but was put in because Webb was scared
of the length of the tubes. The boiler was longer than any other which had
been put on an engine at that date, and he was afraid that trouble might
happen owing to the tubes being too long. Since then, of course, very much
longer tubes have been used. "In what the Author calls the combustion chamber
Mr. Webb placed, if I remember rightly, a soot blower, so that the tubes
could be easily and quickly cleaned. An ash hopper was also provided."
Mr. W. A. Stanier: (pp726-8) stated that
he had enjoyed very much the analysis which the Author has made of our boiler
problem; it has been, he thought, more complete than most of the analyses
seen. As he has indicated, he has perhaps not given due weight to the firebox
volume, but he has gone a long way towards endeavouring to evaluate the various
bailer propartions which have been used on the engines of comparatively recent
times.
It may be of some interest if I give an indication af the free areas
in use on the present L.M.S. engines. As you know, Dr. Wagner indicated the
importance of getting in balance the areas through the small tubes and the
areas through the large flue tubes. On the Pacific" Coronation" engine the
area through the small tubes is 3.23 sq. ft. and through the large tubes
3.66 sq. ft., making a total of 6.89 sq., ft. On the "5X" 3-cylinder engines
the figures are 2.22 sq. ft. and 2.52 sq. ft., making a total of 4.74 sq.
ft. You will remember that in his Paper (253)
Dr. Wagner gave particulars of a boiler which had a free area through
the tubes of something like 8 sq. ft. The comment of a member of my staff
was that that engine would burn brickbats! The difficulty
is, of course, to obtain the free areas which you want and to maintain a
balance with the grate area and the firebox volume within the load gauge
from which we suffer in England.
In connection with the "5X" engines, it may interest yau to know that
the L.M.S. have recently carried out some accelerated train trials between
Glasgow and Leeds and Leeds and Bristol with "5X" engines. With a train weighing
300 tons, the coal consumption on that engine to do the work varied from
40 lb. per sq. ft. af grate area per hour to 100 lb. per sq. ft. of grate
area per hour, which I think indicates what an extraordinarily flexible
steamraiser a locomotive boiler is. I do not advocate an engine being used
to burn l00 lb. per sq. ft. of grate area per hour; I think that if we did
that with some of the bigger engines we should have to put in a mechanical
stoker.
The Author has referred to smokebox vacuum. It may be of interest
to mention that the vacuum in the smokebox of the L.M.S. turbine locomotive
with one nozzle open is just over 1 in. of water, and with two nozzles it
is 2 in., so that with the maximum number of nozzles open it is 6 in.
The engine steams quite well on the fast trains between Liverpool
and Euston of something like 500 tons weight. It seems to me that that is
a comparatively low vacuum in the smokebox for a big boiler, when account
is taken of the vacuum which the French engines are obtaining with the Kylchap
blast pipe, and one of the investigations which I think that every locomotive
superintendent within my memory has carried out is an investigation to endeavour
to improve the vacuum in the smakebox withaut increasing, and in fact decreasing,
the back pressure in the cylinders.
When I was in the drawing office, there was a drawer full of experiments
which had been carried out in connection with blast pipes and smokebox
arrangements, and I am sure that in the. drawing office which I now control
there are similar quantities af experiments, but I do not think that even
yet we have determined what is the most efficient arrangement.
The Author has referred to sinuous tubes. One af the difficulties
in a locomotive is to keep the tubes clean, and there are quite enough
difficulties at present in keeping a flue tube with a superheater element
in it clean af smokebox ash and soot. The old dodge af the driver of putting
a little sand on a shovel and putting it in the firehole door to scour the
tubes has been developed an the L.M.S. and some other railways by introducing
sand guns for this purpose.
E.S. Cox: (736-7) referred to the Midland compounds
and postulated that if you look after the capacity of the barrel portion
of the boiler the rest of the boiler will look after itself. Now, the Midland
compound is a rather interesting example of quite the opposite school of
thought. 'This engine was designed at a time when special steels were not
available and when very severe restrictions were placed on the weight which
was allowed to run over the track; and, being desirous of obtaining the greatest
possible boiler power in that engine, the designer fitted a very large firebox
to a very small barrel. The barrel was only about 4ft. 7in. diameter at the
front end, and the tubes only 12ft. 3in. long, but the grate area was 29
sq. ft., very nearly the equal of that carried by many 4-6-0 engines to-day.
From the steaming point of view that engine has always been very successful,
and I think that that goes to show how difficult it is to arrive at any set
of formulae which can adequately portray all the variations of which locomotive
boiler design is capable. The Author could hardly hope to put into his Paper
many direct comparisons between different locomotive types without drawing
a little fire from his audience, and, still on the question of the Midland
compounds, I have to join issue with him when he says that these engines
"are extremely economical in coal and water and not extravagant in other
running costs, but they undoubtedly have limitations in load capacity which
must make them less valuable to the traffic department than other locomotives
of lower thermal efficiency" Actually, I think it can be demonstrated that
the contrary is true. Many members here must be familiar with their behaviour
in Scotland, where until quite recently they have been hauling trains of
400 tons in weight, and I myself have been behind one up the Shap incline
with a 350-ton train load when the five miles were run in 8½ minutes,
as against a booked time of 11 minutes, certainly without any fireworks or
the engine blowing itself to pieces. On the other hand, as regards economy,
while the economy of these engines was marked in the days when all contemporary
engines had only a very short valve travel and a short lap, I think figures
have already been published in the Press which indicate that the Midland
compounds cannot show the economy of present-day simple machines with modern
valve events.
With regard to the Author's praise of the locomotive boiler generally, we
can only agree with his admiration, but I think he has been a little carried
away by his enthusiasm and is perhaps a little too satisfied. Sometimes when
we see the work which has to be done in the sheds and see these Stephenson
boilers undergoing repairs in the shops we have a little qualm of conscience
that all is not quite as well as it might be, and we feel that new forms
of boiler will keep obtruding themselves on our notice until it may be that
some day the Stephenson locomotive type will be superseded, certainly to
the extent of getting rid of the fat surfaces and the boiler stays, which
give us so much trouble.
Finally, I should like to refer to the Author's assumption of a temperature
in the firebox of 2,500°F., presumably at the point where the gases
are entering the flue tubes. From all the test data which I have seen, I
think this figure is more representative of the temperature in the fire itself,
say just above the actual surface of the firebed ; and, if that temperature
actually obtained at the entry to the tubes, the firebox would hardly be
absorbing any of the heat generated. Tests at Illinois and Altoona show that
the temperature of entry to the tubes is more in the region of 1,700°
to 1,900°, and this, of course, will have some influence, even if possibly
only a slight influence, on the figures which the Author has given.
K. Cantlie (pp. 738-42) submitted a graph (Figure
9) which compared the boiler performance at speeds from 0 to 70 mile/h of
the following locomotives: "his" 4-8-4 for the Chinese National Railways;
the Lord Nelson type with new boiler; and same type with original boiler;
the enlarged Claughton/Patriot boiler; the original Claughton boiler; George
V; Precursor, Teutonic; Greater Britain and Jumbo (comparitive performance
was in descending order as listed).
J.G.R. Sams (744-5): Very sorry to read author's
rather unkind remarks about compounds, because, having had a great deal to
do with ships, he was still unrepentantly of the belief that the compound
locomotive would come, and would suggest a high pressure compound engine,
with a pressure of 300 to 350 psi, with forced draught, and perhaps heated
forced draught. In that connection, he believed that the GER. tried a forced
heated draught with some of their oil-burning engines. They had some sort
of serpentine in the smokebox and led the air in through a mouthpiece just
under the smokebox door, but the serpentine burned away fairly quickly ;
but in these days of special steels we might be able to have something of
the sort, and think that the forced draught would do away with the variations
of blast and vacuum in the smokebox; in fact, we would have no vacuum in
the smokebox, and that might work better than the existing system. With regard
to feed-heating, he considered a short boiler gives room for feed-heating
as well as heating the draught, and that is a point which might be considered.
I hope, however, that we shall never go in for sinuous tubes, because with
the long runs which are common nowadays-and I hnve had to do with runs of
24 hours without there being time to clean the tubes-it i s hard enough to
keep a straight tube clean, and if we go in for sinuous tubes these long
runs might be impossible owing to the tubes choking up. I think we shall
have to keep to straight tubes, or at any rate to fairly straight tubes.
I should like to make a remark about the ephemeral improvements to which
the Author refers. At Crewe, where I served my apprenticeship, I believe
Mr. Webb tried four different variations. Thcre was a figure eight firebox
and a wet-bottom firebox, both having water underneath the fire, and a
characteristic of both was that, owing to the lack of circulation, it was
quite possible in cold weather to have icicles underneath, although the boiler
was in full steam; I have seen them. 'Then on one of his 6-coupled coal engines
he tried brick sides, but the bricks rattled down, and it finished up as
a stationary boiler in the brickyard opposite No. 8 erecting shop. In addition
to that, there were some coal engines built with a circular Lancashire tube
firebox. Why they failed I do not know. I believe the L. & Y.R. also
had some of them. They do not seem to have prospered, and, as the author
says, the original Stephenson design has always pulled through.
E.A. Langridge:(747-8) The Author is to be congratulated
for the immense amount of work he has put in in “grinding out”
so many of Lawford Fry’s formulae, which is a tribute to his thoroughness.
Lawford Fry’s theories on heat transfer and gas flow do not appear,
usually, to have had the attention they deserve, for in many cases, at any
rate, the smokebox temperatures given by these formulae approximate very
nearly to that obtained in practice, at the mouth of the particular tube
calculated for. Since the publication of Dr. Eale’s paper on Gas Analysis
Tests, more reliable data is available than hitherto in the way of firebox
temperatures and vacua, making less assumptions necessary to work out Lawford
Fry’s formulae.
A weak point in the Author’s Paper seems to me the conclusions drawn
from figures which bring into account engine performance as well as the boiler
performance of the locomotive; it is an old observation that the boiler knows
to what engine it is fitted. Mr. Cox has dealt with the Author’s
observations on the Midland compounds. I would point out also that the same
boiler as fitted to the cornpounds was also used ofi Mr. Deeley’s now
defunct 990 class, two-cylinder simple 4-4-0’s which were, I believe,
good steamers and bad economisers ; comparable with the L.N.W. 4-4-0’s.
The Author makes a good point on page 716 concerning effective gas area.
Pushed to its conclusion it means that the ratios of free area of the tubes
to grate area of various boilers are not comparable unless the mean hydraulic
depths, or the A/s. ratios, are the same. As this is generally accepted to
be best at 1/400, or tube bore to length 1/100, one has fairly reliable data
on which to base those proportions, but a consideration of the above, points
to the fact that tube resistance is the thing that matters. If this 1/400
ratio is not worked to it is an easy matter to push up the nominal free area
to a figure not representative of its true value. D. Drumrnond tried a boiler
—at any rate I have seen a drawing of it—in which he employed one
single large flue, instead of tubes, within an ordinary standard locomotive
boiler, which had two large nests of crosswater tubes at approximate right
angles to each other, across the large flue—in a similar manner to his
famous arrangement in the firebox. One might say that the A/s value predicted
failure here. Possibly the L.N.E.R. 10,000 suffered from the same defect.
Likewise the two “Claughton” boilers, mentioned on page 705, may
not necessarily be different in performanre merely because of the tube sizes.
When history comes to be written, it is hardly likely that the boiler proportions
will be connected with the swift demise of these engines. Again, it should
be remembered that the published sizes of tubes for Mr. Stanier’s 5X
boilers is 17/8in. dia. by 13ft. 3in. long, which rather challenges the
Author’s conclusions. I think firebox volume is important and, as advocated
by Mr. Rowland, the firebox should be, ideally, cubical so as to give the
max. volume for surfare necessary. Thus a boiler like the L.M.S. “
Coronation ” is pretty well ideal, the sloping sides being necessary
for cab window look-out, the Belpaire top helping to maintain the cubical
shape as far as possible. The ditference in firebox volume probably accounts
for the difference in performance of many early 4-6-0s, with shallow boxes,
and corresponding 4-4-0s with deep boxes as, for instance, the L.S.W.R. T14
and D15 classes.
I woiild like to suggest that the Author adds a bibliography to the end of
his valuable Paper, including the series of articles in the Railway
Engineer of about 1918, Mr. Lawford Fry’s article in
Engineering of 1921, and Mr. Poultney’s paper to the World Power
Conference of 1923, which latter contains a further bibliography also; and
also Mr. Rowland’s paper on superheating in
our Proceedings of some years ago. The latter has much interesting matter
on tube resistance.
Meeting in Montevideo, Uraguay, 9 and 10 April, 1937. 764
The First Quarterly Meeting of the South American Centre was held
in Montevideo on Friday and Saturday, the 9 and 10 1937. By kind permission
of the Management of the Uruguay State Railways, a trip was made in one of
their Brill railcars from Montevideo to the town of La Paloma on the coast
of Uruguay. The distance, with the exception of two stops, was covered in
3 hours 50 minutes. The Members of the Institution were the guests of the
Management of the Uruguay State Railways. The return journey was made the
same afternoon to the Central Station in Montevideo, which was reached at
7.50 p.m.
On 10 April a Meeting was held, by kind permission of the Management of the
Central Uruguay Railway, at the Peñarol workshops, when Paper No.
362, entitled “ The Most Suitable Passenger Locomotive for Intensive
Use and for Long Engine Runs,” presented before the Institution by Mr.
H. P. Renwick at Bombay on 28 July 1934, and published in Journal No. 134,
November-December, 1936, was discussed.
Critchley, R.P. (Paper No. 379)
Mechanical coaling plants. 780-808. Disc.: 808-13. 21 illus.
Fourth General Meeting of the Scottish Centre, Session 1936-37, was
held in the Society’s Room of the Royal Technical College, Glasgow,
on Thursday, 21 January 1937, at 7.30 p.m. Mr. G.A. Musgrave in the Chair
Based on overall British practice, with some emphasis on early LNWR and LMS
installations at Crewe (North and South) and Springs Branch and LNER
installations at Doncaster, Kittybrewster (Aberdeen) and at Eastfield and
Kipps in Glasgow. The small plant at Hitchin was also described. The Southern
Railway plant at Nine Elms was described.
Discussion: K.R.M. Cameron (809-10): One of the drawbacks with the
present type of plant is that I have yet to see one with more than two bunkers,
and more than two are necessary if one is to handle more than two grades
of coal efficiently. There is some good coal and some bad coal in Grade I
, and it would appear that some further grading is necessary. One grading
is, that you should have the very best first grade coal for long-distance
express passenger engines, second grade for express passenger and long-distance
freights, third grade for local and mineral trains, and the poorest quality
in Grade 4 for shunting engines. This is certainly ideal, but you need four
bunkers in order to keep all grades separate, or two coaling plants, and
I am sure the railway companies would not stand the capital expenditure.
With the old method of hutches, you could have a variety of hutches and
distribute them accordingly. Anti-breakers are one of the good points, provided
you get large coal from the colliery, but the coal is handled so many times
in some plants that there is bound to be some breakage. It is loaded into
the wagon, the wagon is up-ended into a skip, and the skip is hoisted some
60 feet into the air. It would appear to me that the best way would he to
handle as little as possible by lifting the wagon up to the top, afterwards
lowering it inside the plant so as to reduce the height through which the
coal must drop. The third point, that of drenching the wagon, the Author
seems to be going to try it. I would like to give him a word of warning,
that is, if he is drenching the wagon and letting it lie over-night, during
frosty weather, he will find, aiter tipping, that the wagon is still full
of coal, Frozen into a solid mass. That is the only disadvantage of drenching
in cold weather. In such cases, prolonged spraying with hot water from an
injector spray cock has to be done, and this will free the coal sufficiently
to enable the wagon to be emptied.