Journal Institution of Locomotive Engineers
Volume 43 (1953)
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Journal No.231.
Den Hollander, F.Q. (Sir Seymour Biscoe Tritton Lecture).
Efficiency in the choice and application of locomotives. 12-28.
Special General Meeting held at the Institution of Mechanical Engineers,
Westminster on 5 March 1953 at 17.30 at which The Sir Seymour Biscoe Tritton
Lecture was delivered: President. C.M. Cock was in the Chair.
The Netherlands Railways. choice of motive power was based on the need for
increased productivity and to reduce fuel costs. There was a high demand
for passenger travel, and this was best met by electric multiple units which
afforded high acceleration. On a few less intensive services diesel electric
multiple units could provide the same degree of acceleration and afford
comparable passenger comfort. On lines with very light traffic diesel railcars
were used. Electrtic locomotives, which lacked the high rate of acceleration
could be used on freight at night and on long distance pasenger services
with few stops. It was considered that electric traction made the most effective
use of fuel, most of which had to be imported into Holland.
Marsh, S.W. (Paper 518)
Recent developments in the use of rubber in railway engineering. 30-60. Disc.:
60-83.
General Meeting held at the Institution of Mechanical Engineers, London,
on Wednesday 17 December 1952 at 5.30 p.m.: Mr. R.C. Bond, Vice-President,
occupying the Chair who apologised on behalf of the President who was absent
abroad,.
Author was Chief Engineer, Andre Rubber Company,
Showed the general made in the use of rubber in the Railway Industry in the
last ten to fifteen years. It is confined solely to Locomotives, Carriages
and Wagons and does not cover signalling and permanent way. It is not intended
to include normal buffing and drawgear springs or auxiliary bearing springs,
as such details have already been covered in past papers, and their use in
the railway field is now well known.
1 . lntroduction.
2. The general advance which has been made in the compounding of rubbers,
including use of the well-known synthetics, also bonding techniques.
3. General explanation regarding the design of rubber mechanical units, including
some already in general use.
4. Units now under consideration and the trend in modern design work
today.
Robertson, A.S. (Paper No. 519)
Limitations of acceleration and braking with electric traction: a study of
the limitations imposed on performance by wheel to rail adhesion and electric
traction equipment during acceleration and braking. 85-115. Disc.: 115-49.
General Meeting held at the Institution of Mechanical Engineers, London
on Wednesday 14 January 1953 at 5.30 p.m., Mr. C.M. Cock, President, occupying
the Chair.
Even on well maintained track, it is probable that small irregularities will
initiate wheel slip, particularly when working at high speed and high tractive
effort. Adhesion values up to and, above 20% can be obtained even at high
speeds, but the probability of obtaining such a high figure at high speed
is uncertain and depends to a large extent on the state of the track.
Journal No. 232
Bond, R.C. (Paper No. 520)
Organisation and control of locomotive repairs on British Railways. 175-216.
Disc.: 217-65+5 folding plates. (incl. 2 col.). 6 iIlus., 4 diagrs., 11 tables.
Forty-second Annual General Meeting. held on 18 March 1953. President
introduced Mr. R.C. Bond.
Main aim was to increase locomotive availability. Defined the classification
of repairs into "heavy" and "light". Selection of locomotives for repair.
Includes mileage/overhaul statistics for several classes as shown below.
AVERAGE MILEAGE BETWEEN PERIODICAL REPAIRS OF PRINCIPAL REGIONAL
TYPES OF LOCOMOTIVES
Region | Class of locomotive | Average mileage between periodical repairs |
L.M. | 4-6-2 "Coronation" | 73,188 |
4-6-0 "Royal Scots" (taper boiler) and 5X conversions | 70,495 |
|
4-6-0 Class 5 | 56,969 |
|
4-6-0 Class 5 with manganese steel liners | 97,291 |
|
2-8-0 Class 8 | 50,361 |
|
2-6-4T Class 4 | 55,579 |
|
2-6-4T Class 4 with manganese steel liners | 79,361 |
|
2-6-0 Class 4 | 90,663 |
|
2-6-0 Class 2 | 104,304 |
|
2-6-2T Class 2 | 83,155 |
|
E./N.E. | 4-6-2 Al | 93,363 |
4-6-2 A2 | 85,671 |
|
4-6-2 A3 | 83,574 |
|
4-6-2 A4 | 86,614 |
|
4-6-0 Bl | 78,396 |
|
2-8-0 01 | 55,616 |
|
2-8-0 WD | 62,624 |
|
2-6-2 V2 | 77,892 |
|
2-6-2T VI | 66,242 |
|
2-6-2T V3 | 66,821 |
|
2-6-4T L1 | 67,213 |
|
Western | 4-6-0 " King" | 78,987 |
4-6-0 "Castle" | 87,424 |
|
4-6-0 "Hall" | 87,942 |
|
4-6-0 "County" | 87,588 |
|
2-8-0 28XX | 86,981 |
|
2-6-2T 3150-81XX | 71,720 |
|
Southern | 4-6-2 "Merchant Navy" | 75,687 |
4-6-2 "West Country" and "Battle of Britain" | 74,650 |
|
4-6-0 "Lord Nelson" | 81,611 |
|
4-6-0 "King Arthur" | 70,995 |
|
4-4-0 "Schools" | 69,851 |
|
2-6-0 "N" | 53,852 |
|
2-6-0 "U" | 68,941 |
A period in months since previous shop repairs was laid down for each class which, casualties excepted, had to elapse before locomotives were considered for shop repairs. This period was based on past experience, having regard to the nature of the service and the annual mileage the locomotives were running. Typical periods laid down for the then new BR standard locomotives were as follows:-
Class 7 4-6-2 15 months
Class 6 4-6-2 18 months
Class 5 4-6-0 24 months
Class 4 4-6-0 28 months
Class 4 2-6-0 30 months
Class 2 2-6-0 36 months
Class 4 2-6-4T 28 months
Class 3 2-6-2T 33 months
Class 2 2-6- 2T 36 months
Consideration was given to the different practices adopted by the
pre-nationalisation companies. Examination of locomotives coming in for overhaul
was considered to be very important. The limits of wear were considered.
The provision of spares was very important, especially boilers. Costing and
efficiency were significant.
Discussion: Opened by R.A. Riddles (pp.
217-18)Mr. R. A. Riddles, C.B.E. (Past-President) in opening the
discussion, said he felt sure that all present would wish to congratulate
Mr. Bond on a very valuable and informative Paper which would add greatly
to the value of the Institution library, and to many private bookshelves.
The system and method of the repair of locomotives on British Railways with
which he had dealt in his Paper undoubtedly emphasised the care with which
such work was undertaken, and it must be a considerable aid to the economy
of the department as a whole. He was not surprised, but very gratified to
find that Mr. Bond turned his back on his nursery and went to Crewe to find
out how to do things! He only wished that Mr. Bond had included in his Paper
his experience when he went to his secondary school at St. Rollox, where
for many months, to his own knowledge, their belt was six days and not eight
and from twelve pits in the erecting shops at St. Rollox no less than eleven
engines, both heavy and intermediate repairs, were turned out every week.
The point of having as few engines as possible in the erecting shop was touched
upon by Mr. Bond, but not empha ised other than the fact that at Crewe the
erecting shop's capacity was controlled by the capacity of the machine shops
to supply the bit and pieces to put back. The alternative was to give the
machine shops so little to do that they were ready to grasp everything which
came off an engine and to get it back on again before it had time to get
cold! By those means at St. Rollox the schedule was so tight that in point
of fact that was what actually happened. either the machine shop, the wheel
shop, the copper shop, nor other auxiliary shops were ever working on something
which was not required, and that was the secret of the belt which Mr. Bond
had emphasised
A rather disturbing feature about the Paper was the statement that 85 per
cent availability could be considered satisfactory. It would not seem to
be satisfactory at all. It might be working towards the goal, but 5 per cent
under or awaiting repair in the works was far higher by a considerable amount
than it was on one particular railway for many months before the war. A desirable
figure for the Author to aim at was in the region of 4 per cent although
it had even been less than that figure. He recalled that his old chief used
to examine the report on a Saturday morning, and if the figure were under
4 per cent, after 12 o'clock he would take Mr. Riddles across to the refreshment
rooms and stand him a drink. If the figure were over 4 per cent Mr. Riddles
had to stand his chief a drink! Fortunately, however, it did not cost him
very much because at that time it was often possible to keep the figure down
to as little as 3.5 per cent.
On the question of days out of service, Mr. Bond talked about eight-day belts.
There were sixty engine pits and the Author referred to engines going through
in eight days. It was true that one or two belts might be longer, but it
would be interesting to know what happened to the other sixteen days in which
the engines were awaiting or under repair. In the last report he saw he found
that an average of twenty-four days were taken at Crewe, whereas in the Southern
Region where belts had not yet been fully started, the same time was taken!
The total repair cost of £24 million certainly made one think, and as
Mr. Bond' rightly pointed out, there was very great scope for efficiency,
which to him meant the judicious spending of money, whereas to some, economy
probably meant not spending it at all! By proper schedules and the proper
attention to detail an attempt was being made at British Railways works to
save money in that way. That gave greater efficiency and to that end perhaps
the Author did not sufficiently emphasise the importance of initial examination.
Not only was it necessary to examine a locomotive within a matter literally
of hours of its coming into the erecting shop, it was essential to ensure
that the work ordered to be done was only that actually necessitated by its
physical condition. In short, a new pair of laces were not necessary each
time one's shoes needed new soles.
In connection with Table IV it would be of interest to know what influence
the new engines had on the exceptionally high mileage of the Class 2 engine.
It seemed extraordinary that the Class 2 engine should have such a high mileage,
and perhaps it was a quantity of new engines which had made that high mileage
average possible. He desired to draw attention to the statement under "Locomotive
Availability" to the effect that the reasons for locomotives not being available
for traffic came under certain heads, the two main items of which were at
works for repairs and waiting works repairs. In his view that was not correct,
and the third item, namely engines waiting for material, was more important
than either. Not only was he grateful to the Author for his excellent Paper,
but he desired to say how much he appreciated the efforts of those engaged
in this very important work, because without their personal interest, nothing
like the story which Mr. Bond had told would have been possible.
Sir William Stanier, F.R.S. (Past-President)
referring to himself as one of the "has beens," said that it was
a long time since he left the locomotive works, but he had been very interested
in Mr. Bond's Paper. The Institution had once more gained that which would
be a book of reference in a great many quarters. In the past the Institution
had been fortunate in having outstanding papers, and now there was another
Paper which would be read with interest all over the world. There were one
or two items which puzzled him, but it might perhaps be due to the fact that
he had been out of touch for so long. For instance, there was the mileage
of the various locomotives set out in Table IV. When he had something to
do with locomotives on the LMS it was considered very important to maintain
the efficiency of the locomotives, and there was a scheme by which engines
were called in for intermediate repair at about 60,000 to 70,000 miles, and
given general repair at about 110,000 to 130,000 miles. The mileage shown
for the various engines in the table was much lower than he would have
anticipated unless, of course, they were taken on intermediate repairs and
it was done in order to maintain a good standard.
When discussing the belt system, the Author stated that the system could
be introduced in erecting shops with cross pits and it would be interesting
to know whether that had in fact been done. He appreciated that it was possible
if the cranes were sufficiently high to lift engines over one another, but
he would like to know whether it had been done. He desired to pay tribute
to the Crewe erecting shop and to the organisatior: connected with i~. The
shop was built in 1924 largely at the instigation of the late Major H. P.
M. Beames, one of whose nght hand men and the one who was responsible for
organising the planning, was Mr. Riddles. He was now reaping the benefit
of his early work. He desired to thank Mr. Bond for placing before the
Institution such a complete report on the maintenance of locomotives.
K.J. Cook (219-20) (Vice-President) said that the paper
was rather a long one and contained a good deal of descriptive matter. It
was, therefore, a little difficult to pick out many points upon which to
speak. He did desire, however, to quote the Author's statement in referring
to the basis of selection for repairs, that" The wide variations in mileage
at which individual locomotives of the same class require attention in the
works, to which reference has already been made, clearly preclude the use
of average mileage between repairs as a satis- factory basis for determining
when the locomotive should be sent to the works." That, Mr. Cook, suggested,
was an illogical statement. Provided there were the fundamentals of accuracy
of repair and close tolerances, for which basis accuracy was necessary, then
the mileage basis should become and was the only really logical basis on
which to make the preliminary selection.
He was rather perturbed to see that so many engines of certain main line
classes required general or intermediate repair at considerably less than
40,000 miles. He suggested it was due to the fact that there was fundamental
inaccuracy. If the basis particulars of the locomotive were dealt with with
real precision, then if the engine fell down before it ran to within a very
close distance of the specified mileage figure there was obviously some definite
cause. From his own experience he could say that where engines were repaired
with basis accuracy and close tolerances, it had been extraordinary how closely
they ran time and time again and right throughout the classes to their average
mileage. In his view there were at least four reasons, three of which were
quoted in the Paper, that could be put forward to suggest that mileage was
really the correct guiding basis for repairs. h. Bond had referred to the
measure of making good wear and tear, and that measure was the mileage run;
unit cost was expressed as cost per mile, and it is also stated that the
costs of maintenance and mileage between repairs were related to design features
as a guide to future policy and practice. He suggested that that was the
simplest method in which to make the selection and the very first question,
with- out exception, which was asked by the Shopping Control was: -what was
the mileage since the last repair? If engines were accurately repaired he
suggested that the mileage was the best and simplest method wbich could be
used.
With regard to the graph in Fig. 2, it would seem that the actual description
of the number of repairs required needed some modification in that repairs
under that definition included new engines. At the present time when stock
was virtually stationary, mileage was made good by repairing or building
and condemning.
Under "Provision of Spares" the Author stated: "At one works" he was
probably referring to Crewe "where the trouble was particularly acute,
the problem was met by building one spare set of frames complete with cylinders,
dragbox and stretchers for each of three numerically large classes of locomotive,
with outstanding benefit to the progress of repairs at a time during the
late war when every locomotive was needed for traffic." According to English
parlance he did not think that that was" playing cricket," as it affected
days under repair and it did not appear that the argument that it had, been
sound financial policy to provide spares to that extent held
good!
J.F. Harrison (220) mainly
noted that the primary loss in time was through shortage of materials in
the erecting shop.
R.A. Smeddle (220-1) commented on statement (page
181) that the frequency of repairs was governed as much by the mechanical
condition of the locomotive as by the boiler. To some extent it depended,
in his view, on which region of British Railways was being discussed. In
some regions it was found that boilers lasted longer between repairs than
in others. If one was fortunate to obtain a large mileage out of the boilers,
it was almost invariably found that there was trouble with worn tyres, loose
axle boxes, etc., although the latter had to a great extent been cured by
the by the fitting of manganese-steel liners to the boxes. That was proved
on reference to Table IV where a great improvement is shown on Class 4 and
5 engines as a result of the use of manganese-steel liners. If the boiler
would hold out, as apparently it did on regions with water softening, then
it was a great help to securing greater mileage between repairs. On the subject
of mileage, he was interested in Table III where the average mileage from
general repair was said to be 64,268 miles. Surely that was rather low. He
extracted the Western Region's figures and found that the mileage was 80,000
and average time in months from general repair 41. It therefore appeared
that the mileage was slightly lower on some of the other regions. The higher
average on the Western Region might be accounted for by the attempt being
made to put the best into the repair of the engines. He had worked on three
regions, but was not so familiar with the LMS, or Crewe, and in his view
the quality of the repairs at Swindon had a great influence on the mileage
which it was possible to obtain there between general repairs and between
general and intermediate repairs, the mileage between the two being approximately
the same. The statement on page 188 that the smaller the number of days taken
to repair each locomotive, the lower will be the number of engines at the
works was interesting. The aim was, therefore, to complete the repairs in
the shortest possible time. He suggested that it might be better to put it
round the other way and reduce the number of engines in the erecting shops.
That was done at a works with which he was previously associated. Weeks were
being taken to repair the engines so a number were taken out of the shop
and the reduction in the number of days as a result was surprising. With
regard to the staging or belt at Crewe, at Swindon there was similar staging
of repairs. The pits are arranged transversely with a traverser in the middle
and engines were moved to the various positions by means of overhead cranes.
R. Arbuthnott (221-3) from the private locomotive
manufacturing industry commented on the huge improvement wrought by the use
of manganese steel axlebox liners, and asked why they had not become universal,
and also asked what improved boiler boiler and was informed by Bond (230):
better water quality, higher standard of shed maintaenance, and improvements
in design: ample water spaces, larfe radii in the bends of firebox plates
and steel or monel firebox stays.
E.S. Cox (223-5) added very little apart from noting that the use
of manganese steel axlebox liners had increased tyre life and that some modern
designs were excessively complex (he was presumably refering to multiple
cylinders).
H.H. Swift (225) noted that a system of progressive repair had been
introduced at Ashford and that this had led to a 10% improvement in
productivity.
I.C. Forsyth (225-8 (3 illus.) described a welding
repair method adopted at Crewe for fitting a pre-assembled front-end onto
the Princess Royal main frames, which indicated that trouble was
experienced through the cylinders working loose and fracturing..
Meeting at Doncaster on 19 April 1953; J.G. Dickson in Chair
R. Hart-Davies (240-1) said that
it was with some trepidation that he spoke on this occasion because, he had
the responsibility of being Chairman of a Committee dealing with Locomotive
Maintenance Standards, and that when he saw the size of the task ahead as
revealed by the Paper he realised it would take a long time to accomplish.
He was puzzled by the figures in Table I in which the mileage obtained between
general repairs is shown as averaging 101,000 for all engines compared wIth
the mileage from general to intermediate repairs of some 64,000.. He was
always under the impression that by the time the boiler received a general
repair the engine had completed two penods in service and that at the halfway
mark, which was the intermediate repair, the mechanical parts were restored
to a state in which they would run practically an equal amount of mileage
before again requmng repairs. He felt that when average figures are taken
results an be misleading and that a more realistic comparison is obtained
from figures for each class of engine separately. He thought that on the
question of mileage between shop repairs it was important that the initial
play and tolerance allowed in moving parts and bearings of all kinds .should
be made as small as possible consistent with proper operatIon to start wIth.
Thus the time taken and miles run before that degree of " knock " develops
which necessitates bringing the 'engine into the works, would. probably be
much greater. He thought this was one of the most Important considerations
in connection with maintenance. The Author mentioned that the statistics
used in his Paper were on a 6-day basis, whereas our present working week
is one of 5 days. He asked if there is any likelihood of a change in the
form of statistics to bnng them to a 5-day basis in the future.
Dymond, A.W.J. (Paper No. 521)
Operating experience with two gas turbine locomotives. 268-336.
Sixth Ordinary General Meeting of the Session 1952-53 held at the
Institution of Mechanical Engineers on Wednesday 18 February 1953 at 17.30;.
C.M. Cock, President, occupying the Chair.
Brown-Boveri gas turbine locomotive No. 18000 and Metropolitan Vickers locomotive
No. 18100. Discussion: Sir William Stanier (pp. 292-3)
made pertinent remarks on the gas turbine locomotives, and the difficulties
encountered with operating the steam turbine locomotive on the LMS
(reproduced in section on
Stanier)
E.F. Spanner (305-6) wrote that a train heating boiler
built into and forming part of a powerful modern locomotive can be a tremendous
nuisance if it fails to function properly, and robs the train of its heating
service. Writing as one personally responsible for a number of train heating
boiler installations he observed that:train heating boilers require: adequate
space, a reasonable allocation of weight, a compartment well ventilated when
moving in either direction and an adequate and non-aerated feed water supply.
Too often the space offered is unduly limited and a good job cramped for
as little as an additional 6 in. on length and 6 in. on width of floor space.
Two principal types of train heating boiler equipment are available: flash
type and lightweight firetube type. There is a fundamental difference between
the two in regard to character . and weight, type first being light
in weight but heavy on maintenance and second being from 25% to 50% heavier,
but of robust and long lived construction. When account is taken of the weight
of fuel and feed water which has to be carried for a normal run, the difference
in weight between type (1) and (2) is reduced to less than 10%. (c) An oil-fired
train heating boiler requires a great deal of air at from 1 to 2 in. w.g.
pressure for maintaining combustion under all conditions, i.e. with the
locomotive at speed in either direction, in the open air and through tunnels,
cuttings and so on. Cases have occurred where excellent results were secured
running" ahead," as as it were, and poor results running" astern." There
have also been cases in which the combination of a restricted compartment,
a boiler of high output and little ventilation has resulted in the operation
of automatic controls being affected. . (d) Feed supply to an oil-fired boiler
is seriously affected by conditions at the suction end of the feed line.
Special precautions should be taken to ensure;(1) that the suction is always
well drowned at all times and under all conditions of acceleration and
deceleration, running around right and left hand curves and so on; (2) that
where possible, arrangements are made to ensure that the water tanks are
filled with inert flue gas rather than air (this involves taking gas from
the boiler flue to the air inlet and air escape to the feed tank); (3) that
good water is used and~the boiler washed out periodically; ( 4) that the
boiler, is filled right up to the crown from the non-aerated feed tank at
each" shut down," in order to prevent air being "pulled back" into the boiler
so causing corrosion above the water level. Attention to all these points,
and to the selection and maintenance of adequate controls is essential to
the establishment of satisfactory running service.
Written communication
G.W. Carpenter (332) wrote that in the Paper the performance of the Brown-Boveri
2,500 h.p. locomotive is compared with that of a King Class 4-cylinder 4-6-0.
The locomotive working details given with the speed distance curves for the
Cowley Bridge Junction-Whiteball and Athelney-Somerton Tunnel sections indicate
that the mean power output of the gas turbine machme was about 90 per cent
of its rated maximum in the first instance and that full power output was
used for the bulk of the second section.
The comparative performance of the King Class locomotive quoted in the Paper
is, however, very moderate in relation to maximum recorded performance. by
these locomotive; in ordinary service. Such runs have. included. times of
20¾ minutes from Cowley Bridge Junction to Whiteball with 417 tons tare
and 23 minutes with 537 tons tare, whilst a Castle Class locomotive covered
the section in 21½ minutes with 460 tons. The performance of the
Brown-Boveri locomotive between Athelney and Somerton Tunnel has been equalled
by a King hauling a practically identical load (381 tons tare) whilst the
comparative King performance quoted has been equalled in ordinary service
with 537 tons tare, a tonnage heavier by nearly 50 per cent.
It is, therefore, reasonable to assume that the performance of the e King
Class locomotive quoted in the Paper was achieved at an appreciably lower
percentage of the maximum power output which these locomotives can sustain
than that of the Brown-Boveri locomotive. The Paper also states that the
sustained high rate of drawbar horsepower developed by the Brown-Boveri
locomotive. Is beyond that normally possible with the maximum continuous
capacity of any steam locomotive in the country. . From published data the
Brown-Boveri locomotive appears to be capable of developing about 2100 h.p.
at the wheel treads at full power output at speeds between 40 and 8O. m.p.h.
Corresponding drawbar horsepowers, with locomotive frictional and air resistance
calculated on the basis of other locomotives of similar weight and wheel
arrangement, may be estimated at 1700 at 80 m.p.h., 1900 at 60 m.p.h. and
2000 at 40 m.p.h.
Sustained power outputs developed at speed by British express passenger
locomotives recorded by competent observers, using train and locomotive
resistance formula which have been proved to give a reasonable degree of
accuracy, indicate that the 4-6-2 type locomotives of the former L.M.S.,
L.N.E. and Southern Railways are capable of sustaining maximum drawbar
horsepowers equal or superior to those of the Brown-Boveri locomotive, whilst
the Kmg Class 4-6-0 locomotives, despite their relatively smaller grate area,
can sustain maximum drawbar horsepowers closely approachmg those of the gas
turbine locomotive. The appreciable penods of time during which these power
outputs were sustamed. would appear to indicate that the boiler capacity
of the locomotive concerned is adequate to sustain such efforts for lengthy
periods, limited only by hand firing. This limitation could, of course, be
overcome by the provision of mechanical stokers, if it is desired to sustain
such power outputs for very lengthy penods.·
Published data for the Metropolitan-Vickers 3,000 h.p. locomotive shows this
machine to be capable of developing 2,400-2,500 h.p. at the wheel treads
at full power output, at speeds between 40 and 80 m.p.h. Corresponding drawbar
horsepowers may be estimated at 2,000 at 80 rn.p.h., 2,300 at 60 m.p.h. and
2,400 at 40 m.p.h. Whilst these values of drawbar horsepower are superior,
at speeds of 60 m.p.h and under, to the maximum sustained outputs normally
obtainable with existing British express passenger locomotives, it is doubtful
If existmg British traffic conditions enable such power outputs to be sustained
for any length of time, except with heavy trains on severe gradients. Should
traffic requirements demand the development of sustained power out-puts of
this order, it is doubtful whether 4-6-2 type locomotives would have adequate
adhesive weight to sustain such power outputs in bad rail conditions. It
may, however, be mentioned that the 4-cylinder compound 4-8-0 type locomotives
of the French National Railways have frequently sustained power outputs of
2,500-3,000 d.b.h.p. over 1engthy periods at speeds between 40 and 80 m.p.h.
even in bad rail conditions. These locomotives weigh 105 tons m working order,
without tender. A simple expansion locomotive of this type with equivalent
boiler capacity should, therefore, be capable of sustaining 2,250- 2,700
d.b.h.p in this speed range, even in adverse weather and rail conditions,
and would appear to merit consideration if locomotives of enhanced traffic
capacity are required.
Journal No. 233
Reed, Brian (Paper No. 522)
Running tests of a 500 h.p. diesel-mechanical locomotive.. 366-97. Disc.:
397-411.
Ninth Ordinary General Meeting held at the Institution of Mechanical
Engineers, London, on Wednesday 15 April 1953, at 5.30 p.m., Mr. C. M. Cock,
President, occupying the Chair.
The losomotive tested was one of two eight-wheel 500 bhp machines built for
Peruvian Corporation for service on the Paita-Piura Railway, a 62-mile line
with short grades of 1 in 29-30 and longer grades of 1 in 35-50, laid almost
entirely without ballast. The specified top speed was 33 m.p.h.; and most
of the freight traffic and the few mixed and passenger trains on this route
were handled by these two 55-ton locomotives, which had been in revenue service
now for a year with satisfaction.
J.F. Alcock (400) remarked that the locomotive
in question was one which he was inclined to look upon as his own locomotive
so that his personal pleasure could well be imagined when Mr. Riddles agreed
to accept it for test on British Railways and especially when the dynamometer
car was made available. He had also been highly delighted when such an authority
as the Author offered to take personal charge of the trials; in fact, the
Author took such personal charge of them that whenever Mr. Alcock happened
to go on one of the runs in order to discuss the matter with Mr. Reed, any
such discussion proved quite impossible because the Author was checking times
against mile-posts with a stop watch in one hand and a pencil and notebook
in the other. There is no doubt that the Author had done an extremely good
job in running the trials and had presented a most interesting Paper. It
should also be mentioned that the consulting engineers, Messrs Livesey &
Henderson and, of course, the customers, The Peruvian Corporation, had been
extremely helpful and co-operative in allowing the delivery of the locomotive
to be delayed while the trials had been carried out.
He would like to make a few comments on special points which he had noted
in going through the Paper. Figure 3, for instance, did not clearly show
that all the bearings were fully self-aligning. All the shafting between
the engine and the gearbox was, in fact, fully articulated in the sense that
any movement in the frames could not produce any stress on any of the details,
an important point which in years gone by, had caused a great deal of trouble
and particularly crankshaft trouble.
On the following page, reference was made to the drivers. There had certainly
been a good deal of trouble due to union restrictions. It was stated in the
Paper that eventually there were four drivers, but Mr. Alcock thought that
there had been many more because each time he had gone to the locomotive,
there appeared to be a different driver in charge. When one enquired about
it, one was told that it was because the driver who had been on for two days,
had a day off, and the man who would be on next week, had come on the day
before, while the man who was on the previous week, had been on the day after
and so on. There was, however, consolation in the fact that the locomotive
was certainly having a good testing.
On page 373, reference was made to the fitting of an excess fuel stop gear
and he would like to explain the detail. All diesel engines, of course, had
excess fuel stops. It was not really a question of fitting an excess fuel
stop, but of modifying the fuel stop. There had originally been thc usual
device which allowed a small amount of extra fuel for starting up from cold
and this had been controlled by a pull wire from the cab. It was, however,
discovered as, looking back, one ought to have appreciated, that if anybody
wanted extra power it was only necessary to pull the wire to obtain it; that
had certainly not been the purpose of the gear and, therefore, modifications
were carried out and the gear redesigned so that this could not occur.
With regard to engine rating, it must be remembered that the locomotives
had been in Peru for a year, and the tests which had been described had been
conducted in 1951. Two years had been taken up in building the locomotives
prior to that and the inception of the idea went back probably another 12
months or 2 years, so that the rating had probably been agreed upon 5 to
6 years ago. He remembered discussing it with the late Mr. Ted Paxman. At
that time the engine had been designed to carry 660 h.p. at 1,500 r.p.m.,
that was, the onehour overload rating. They decided to derate about 25 per
cent, 10 per cent being taken oft the speed, bringing it down to 1,375 r.p.m.
and 15 per cent off the fuel loading which gave a figure of 500 h.p. at 1,375
r.p.m. Mr. Alcock regarded it as a very suitable rating for the cngine in
every way. As will be seen from some of the curves, the torque of the engine
began to fall away at about 1,050 r.p.m. at which speed peak torque was obtained.
As is usual on a diesel engine when it begins to stall down from maximum
speed, torque increases until peak torque is reached. This gives an excellent
self-compensating effect and it can be seen frequently on the dynamometer
curves that the engine can hold on somewhere about 1,100 to 1,200 r.p.m.
and it is only when the duty becomes too onerous and the engine stalls below
the peak torque position at 1,050 r.p.m., that a gear change down has to
be carried out.
On page 381, the question of wheel slip was raised, a very interesting point.
As the Author said, there was hardly ever any real slip which amounted to
anything. That was quite understandable. When a wheel slips, there is an
immediate reduction in torque; as a consequence the engine speeds up and
the automatic governor then immediately shuts down the fuel, consequently
the wheel slip is checked almost instantaneously while the driver, with a
somewhat slower reaction than the engine governor, checks back on his throttle
control and so gains control again within less than a second. He then picks
up the throttle again until the engine is on load and, as shown by the
dynamometer charts, the slip is hardly measurable in time, while the tractive
effort has only been reduced by about 30 per cent. In practice, the effect
really was amazing. The same type of thing occurred exactly whether the friction
clutch was fitted or the hydraulic coupling. He hoped shortly to make a similar
test with a hydraulic torque convertor, but he did not think that quite the
same result would be obtained, although it certainly should be a great deal
better than the result obtained with. a steam locomotive. The problem, of
course, on a steam locomotive is that however quickly the driver might bring
back his regulator, there was always a considerable amount of steam in the
steam pipe and steam chest which had to get away through the cylinders before
the driver could take control again.
Reference to a steam locomotive slipping brought his mind back to an incident
which occurred some months before the diesel locomotive went on trial. He
decided to make a trial run over the same track on which the tests were to
be carried out. A steam locomotive was, of course, on the job. He chose,
as it happened, the worst possible morning-foggy and wet with autumn leaves
on the track and it certainly had been an experience, in fact, to anyone
except a railway man, a terrifying experience. Slipping and severe slipping
was occurring every few moments and the driver had his work cut out to control
it. The train, on several occasions, almost came to a standstill and there
was danger of it running backwards down grade. The fireman certainly had
all his work cut out looking after his own job. There were, of course, several
tunnels, one of them only 100 yards long, but it can be imagined that it
seemed very much longer when slipping. Slipping in a tunnel for any length
of time is not a pleasant experience and it really was remarkable to see
the ease and simplicity with which the diesel locomotive carried out much
more onerous work at a later date. Mr. Sinclair, in his remarks, had made
it obvious
Discussion: O.S.M. Raw (405) asked whether the gearbox
was running in Peru in the appallingly noisy state which had been mentioned,
or whether it had been silenced; also what was the cost of the locomotive
the tests of which were described in the paper. It was admittedly, he added,
a completely prototype locomotive, so that cost might not afford a fair basis
for judgment, but it would be interesting to have an idea of what an electric
transmission locomotive of the same horse-power would cost compared with
the one in question, based on the same numbers for production and communicated
that Cantlie had very wisely commented on the fact that the troubles with
the fluid coupling should not be stressed. They are normally most reliable
and trouble free as the writer found from experience having maintained a
large number of them which were fitted to large diesel engines used on oil
well drilling rigs. He felt that there must have been some maladjustment
in the one on the locomotive under trial and he expressed surprise that the
matter was not referred to the makers at the time, or before, the locomotives
yere shipped to Peru. It would appear that they were not properly adjusted
before shipment as he had heard that on one locomotive it has been removed.
Having been at the receiving end abroad the writer strongly urged that nothing
should be shipped out unless it is proved to be absolutely right.
With regard to the gearbox noise we are informed that this has been somewhat
improved. The real point is not to have excessive sound which has to be damped.
The writer suggested that if it is not a case of insufficiently stiff shafts
or bearings inside the box that the noise is greatly amplified by the shape
of the box which is a simple rectangle in shape with a flat lid, a shape
which seems to have been specially designed to augment any noise which it
may produce.
It is essential that they must be properly clipped up and supported. In addition
the trouble can be caused if these pipes are not properly annealed when they
are made, and they must be re-annealed at regular intervals. Also, trouble
can be occasioned by constant polishing and this might well occur overseas
and in Peru where labour to maintain locomotives properly is still available.
In the Army in the last war it had to be forbidden by order to polish copper
fuel and other pipes. Ex-cavalry regiments full of zeal for "spit and polish
" kept these pipes on the armoured vehicles and lorries beautifully polished,
yet this was the cause of many deaths in the desert due to the constant polishing
Mention has been made of trouble from fractured oil pipes. causing the pipes
to fracture on service so allowing the crews to be stranded. Orders forbidding
the polishing of copper pipes and that they should be regularly annealed
are essential. A still better improvement would be to make such pipes out
of solid drawn steel. It has been stressed that trouble has not been experienced
with the main components, but only with the auxiliaries. This is the case
with all locomotives, but in a steam locomotive the failure of an auxiliary
is not so vital, whereas on a diesel locomotive it usually results in the
complete failure of the locomotive.
In conclusion the writer enquired why a rigid 8-wheeled design was chosen
for a sinuous line. The previous steam locomotives were eight-couplcd, but
the writer fet sure that they had leading pony trucks.
Morgan, R.E. (Paper No.523)
The development of the Farnboro electric indicator and its application to
the steam locomotive. 412-21. Disc.: 421-5. 6 diagrs.
Fourth Ordinary General Meeting of the Manchester Centre held at Reynolds
Hall on Thursday 26 February 1953 at 6.30 p.m., the chair being taken by
Mr. D. Patrick.
Also reviews locomotive indicator development in general including mechanical
Indicators, e.g. Dobbie McInnes and Maihak. These indicators are simple in
design and use and lend themselves to easy calibration under static conditions.
They require some form of reducing mechanism, usually in the form of a linkage
system driven from the crosshead, since in most cases the size of the diagram
is only of the order of 3 in. x 1½ in. The pressure measuring element
has appreciable inertia and this can easily lead to spurious effects, especially
at the higher engine speeds. They are usually used for stroke base diagrams,
but are adaptable.
Optical Indicators-Cathode Ray type, e.g. Cossor, Dodds. These indicators
then required "complicated electronic systems" and produced small diagrams.
The inertia effects are negligible and they can be used on either crank angle
or stroke base. In most cases the pressure measuring element is sensible
to changes in temperature and this must be compensated for. This type of
indicator is very suitable for extremely high engine speeds and is chiefly
used for comparative analysis of cylinder events. A high speed cine camera
was often employed when these indicators were in use. Both mechanical and
optical indicators give an indicator diagram for each cycle of events.
The Famboro Electric indicator was simple in design and easy to operate.
It is designed to be driven from the axle or crank shaft of the engine and
the diagrams, 14 in. x 7 in., are usually taken on a time base. The inertia
of the pressure measuring system is negligible even at high engine speeds
and the indicator is quite simple to calibrate.
These indicators give diagrams on either a stroke base or a time base or
both. The stroke base diagram has the major advantage of permitting the easy
computation of i.h.p., but this is really the only thing to be said in its
favour. On the debit side are : the size of the drum, and therefore the diagram,
must be small to reduce inertia effects due to rapid acceleration at high
speeds. Secondly, the diagram is cramped at the ends where the principal
valve events occur, that is, lead, cut-off, release, depending of course
on speed, and a 3 in. diagram does not lend itself to accurate analysis from
this point of view, if the effects of deliberate changes in valve events
are to be analysed.
With the introduction of large scale testing of locomotives by British Railways
after WW2, the problem of the most suitable type of indicator for use on
a steam locomotive had to be decided. Spring and piston indicators of the
Crosby type had been generally employed for indicating trials on the road,
and experiments with cathode ray type indicators had been carried out prior
to the war both by the LNER and LMS, but the results were inconclusive. The
decision reached was that the Farnboro indicator appeared to be the most
suitable and after consultation with Messrs. Dobbie McInnes, manufacturers
of this type of indicator, two of these machines were ordered, one to be
used at Rugby Locomotive Testing Station, the other by the MTUs for
trials on the line.
It must be stated here that the Farnboro indicator was not originally designed
for use on a steam engine, but was principally intended for the indicating
of piston type aero engines, both on the test bed and in flight, but it was
hoped that the special type of pressure element supplied for use on a locomotive
would overcome possible difficulties caused by condensation occurring on
the insulating material used in the element.
The Farnboro system consists essentially of a pressure measuring device and
a machine on which to record that pressure at its appropriate piston position
The pressure measuring device, known as the element
is located in the cylinder cover of the engine being indicated. The element
has a shuttle piston which is subject on one side to cylinder steam pressure
and on the other to a reference air pressure which can be varied as required
by means of a control cock on the indicator. This piston, whose movement
is restricted by electrical contacts, is free to move under the influence
of either air or steam pressure depending on which is the greater of the
two.
Discussion: J. Fore (p. 422) asked how the system was adapted for
four-cylinder locomotives and was informed that in the case of a four-cylinder
engine (8 beats per revolution) the dead centres and therefore the diagrams
would be spaced at approximately 45 of crank angle. When the locomotive
had only 4 beats per revolution then there would be no alternative but to
take two separate cards, and accept the time interval between them, care
being taken to ensure that the boiler pressure and speed remained the same
for each card.
D. Patrick (p. 421) had opened the discussion and received the following
response: the matter of all cylinders being indicated simultaneously was
a most important point in favour of the Farnboro indicator. The diagram for
each cylinder end was formed as had been described earlier, but four or more
elements could be used, each element recording by means of the spark which
punctured the paper the exact point at which the reference air pressure was
balanced by the cylinder steam pressure and its appropriate phase position.
Considering one revolution, each element gave two sparks, then for a two-cylinder
locomotive eight sparks per revolution would be recorded, all on the same
pressure ordinate, but correctly spaced in accordance with the angle between
cranks, and the cut-off of the locomotive concerned.
.
Journal No. 234
Bond, Roland C. (Presidential Address)
Years of transition. 439-63 + 4 folding plates. 15 illus., 7 diagrs.
This address surveys the post 1923 period in broad economic/technological
terms. It reflects the policies of Bond's former chief (Stanier). Bond
examined six experimental locomotives:
1. Armstrong-Ramsay Condensing Turbine Locomotive.
2. Beyer-Ljungstrom Condensing Turbine Locomotive.
3. Schmidt-Henschel High Pressure. LMSR 4-6-0 6399.
4. High pressure compound with water tube boiler. LNER 4-6-4..
5. Non-condensing Turbine Locomotive. LMSR 4-6-2. 6202.
6. Simple expansion 0-6-6-0 "Leader" Class. Southern Rly:
Of these locomotives the most successful was, I think, the LMSR condensing
turbine locomotive No. 6202. It ran 439,931 miles in earning service; and
although fuel economy was limited to that which could result from a reduction
in heat losses compared with a reciprocating engine working between the same
temperature and limits, dynamometer car tests showed a saving in coal consumption
of approximately 7 per cent. Certain mechanical troubles were experienced
and the availability record of the locomotive was not As a result of the
experience gained over a period of 15 years, decided to convert this locomotive
to 4-cylinder simple propulsion..
The LNER high pressure compound locomotive did not come up to expectations.
It was fitted with a water tube boiler in which the hot gasses were drawn
horizontally from the firebox by way of a series of baffles through the forward
banks of water tubes. It was soon apparent that the circulation was
unsatisfactory and, in view of the steaming difficulties expeiienced, a full
size model of the front portion of the boiler was constructed and experiments
carried out which revealed that short circuiting of the gases was taking
place. Considerable modifications were made to the arrangement of the baffles
in an endeavour to bring the products of combustion into contact with the
whole of the forward banks of water tubes. As originally built, the locomotive
had two high pressure cylinders 12 in x 26 in. and two low pressure cylinders
20 in. x 26 in. but, as a result of the steaming difficulties, the high pressure
cylinders were subsequently reduced to 10 in. in diameter. In spite of the
modifications to the boiler and the reduction in the diameter of the high
pressure cylinders steaming was only satisfactory when the locomotive was
developing high power at long cut-offs, with a smokebox vacuum in the region
of 6 in., and under these conditions the smokebox temperature was too high.
Some slight improvement was effected by fitting twin blast pipes, but
notwithstanding the various alterations carried out this locomotive did not
prove economical and, in general, it burnt considerably more coal than the
standard Pacifics. It was therefore rebuilt as a 3-cylinder
simple with a boiler of standard design working at 250 lb./sq. inch.
Nor was the Schmidt-Henschel LMSR 4-6-0 Fury successful. Repeated
tests and many modifications were made over a period of two years in attempts
to make the boiler steam. Combustion was not good, steaming was always most
unreliable and coal and water consumption excessive. Fury was never
able to take its place in normal service. One serious tube explosion occurred
and the locomotive was rebuilt and appeared as No. 6170 British Legion,
becoming the prototype for the converted Royal Scots, one of the most
successful 4-6-0s ever to run in this country.
Neither of the two condensing turbine locomotives fulfilled expectations
under the traffic conditions of the Railway on which each was respectively
tested. The Ramsay locomotive was designed to give a performance
approximately equal to the LNWR Claughton Class express passenger
locomotives. It was found on arrival at Horwich for tests, to be considerably
above the designed weight and its route availability was thus severely limited.
The results of trial runs were most unsatisfactory. The forced draught system
did not allow proper combustion to take place and the boiler pressure could
not be maintained, even when running light. The inability to steam was also
due to the fact that the condenser, instead of producing a vacuum of 27½
in. for which the turbine was designed, was frequently unable to reach 20
in. Many modifications were made and further trials conducted, but the
performance both of the boiler and condenser was still inadequate. When the
vacuum fell slightly the demand for steam increased rapidly and could not
be met; the pressure fell and the turbine, being unsuitable for a lower pressure,
could not take the load. Coal consumption was very high in relation to work
done.
The Beyer-Ljungstrom locomotive was tested over a period of eighteen months
on passenger and freight trains on the Midland main line, including St.
Pancras-Manchester express passenger trains. Good time was usually maintained
with trains of normal loads and while the boiler steamed well, condenser
vacuum varied rather widely and was particularly susceptible to the effects
of running through tunnels. Coal consumption was, in general, no less than
with normal locomotives engaged on similar duties.
The most recent example of the unconventional was the Southern Railway Leader
Class in which two 3-cylinder totally enclosed sleeve valve engines were
mounted on six-wheel bogies with all weight available for adhesion. The boiler,
off-set from the longitudinal centre line of the frames, was of all-welded
construction, the firebox heating surface consisting essentially of thermic
syphons enclosed by solid firebrick walls. Since the high availability and
reduction in maintenance costs and fuel consumption which were aimed at,
are just those things for which we are continually striving, .the utmost
pains were taken in attempting to overcome initial troubles and to give this
unusual design every opportunity to prove its worth. A number of modifications
were made and many trial runs were undertaken, but the locomotive could not
be made capable of sustained work or reliable performance. The principal
causes of trouble were breakages of valve gear parts, fracture of the crank
axles and difficulties with the brick walls of the firebox. The engine weight
was excessive and its distribution faulty, the firing cab was excessively
hot and most carefully conducted dynamometer tests showed there to be no
improvement in thermal efficiency. The disappointing results which have attended
the effork to break away from normal lines of development in this country
are typical of ,experience generally.
Type | Mileage |
Eastern Region A1 (then almost new) | 93,363 |
Western Region Castle | 87,424 |
Eastern Region A4 | 86,614 |
Southern Region Lord Nelson | 81,611 |
Western Region King | 78,987 |
Southern Region Merchant Navy | 75,687 |
Southern Region West Country | 74,650 |
London Midland Region Duchess | 73,188 |
London Midland Region Rebuilt Royal Scot | 70,495 |
London Midland Region Class 5 4-6-0 | 56,969 |
The largest single source of further economy in steam traction costs is in reduction of expenditure on maintenance in shops and sheds. Although the average mileage between repairs in works has increased by nearly 30 per cent during the last thirty years, there is considerable scope for further improvement. The average mileage between consecutive general and intermediate repairs for all steam locomotives is approximately 65,000 at present. But many of the most modern types, both large and small are proving themselves capable of running more than 100,000 miles before requiring heavy repairs in the shops. This result has been attained by a constant process of elimination of weaknesses in design, material and maintenance methods. More can yet be done by extending chemical treatment to improve the quality of boiler feed water supplies. As the proportion of new locomotives embodying those features of advanced mechanical design which have been found to contribute most to higher mileage between repairs increases, and others with some years of service ahead of them are modified in the same way, there is no reason why the average mileage between repairs should not be substantially increased without any loss of operating efficiency. Finality has not by any means yet been reached, and the target at which we must aim is an average mileage of at least 100,000 miles between consecutive repairs in shops. Better axle bearings, harder tyres and rotary valve gears may assist still further in this respect and, as I pointed out in a Paper on (' Locomotive Maintenance " which I recently read to you, the stimulating effects arising from the critical examination to which every phase of the maintenance organisation has been subjected during the last five years will be felt to an increasing extent in the future, and will apply alike to all forms of traction.
Micklethwaite, N. (Paper No. 524)
Distribution of fuel on British Railways with regard to coal and coke. 464-73.
Disc.: 474-5.
Fifth Ordinary General Meeting of the North Eastern Centre held at
the Danum Hotel, Doncaster, on 29 January 1953 at 7 p.m., the Chair being
taken by Mr. D.C. Stuart.
Next to wages fuel was by far the greatest expense in the motive power
department. In 1951 coal and all fuels, the vast majority being coal, cost
£38 million as against an overall wage bill in the motive power department
of £45 million. The coal consumed was 13,549,000 tons in all regions,
the Eastern and North Eastern Regions using 2,600,000 and 1,097,000 tons
respectively. These figures were not decreasing and it was therefore our
main aim to keep these costs as low as possible
Compton, J.N. (Paper No. 525)
The design and construction of steel fireboxes. 475-96.
Third Ordinary General Meeting of the North Eastern Centre held at
Great Northern Hotel, Leeds on 10 December 1953 at 6.45 p.m., the Chair being
taken by Mr. J.G. Dickson.
The author probably worked for the Yorkshire Engine Company. Advantages
of copper fireboxes:
(i) Superior conductivity with the result that the rate of heat transfer
is higher than with steel, in spite of the necessity for using a thicker
section.
(ii) Long life: even with water of low alkalinity corrosion is negligible.
(iii) Easy material to work under manufacture and comparatively easy when
repairs by patching are required provided particular skilled labour is
available.
The disadvantages, and therefore the advantages of steel fireboxes more than
outweigh the advantages:
1 . High cost even after setting off higher scrap value.
2. Necessity for riveted construction. Although copper fireboxes have been
constructed by welding, both in Britain and on the continent, it cannot be
said that it is accepted practice, and copper fireboxes continue to be built
by the riveting method. The disadvantages of riveted lap joints are cost
of manufactures, the skill required involving what must be looked upon as
a declining trade and the localised overheating and concentrated stress resulting
in the development of cracks particularly in the region of the caulked
seams.
3. The adoption of steel for fireboxes presents a comparatively simple
fabrication which can be built up by arc welding of butt jointing seams with
comparatively thin plate. Evcn the tube plate need be no thicker than ½
in. for normal steam pressures instead of the specially thickened up copper
tube plates which are nccessary to ensure against tube leakages. It wais
an obvious scqucl to weld the tube to the tube plate. The other plates are
usually only 3/8in. instead of ½ in. necessary for copper,
and therefore the loss due to non-conductivity is reduced considerably, and
there is no discernible disadvantage due to the slight slowing up in the
rate of heat transfcr.
4. The whole steel firebox can be stress relieved after welding and before
insertion in the firebox shell for staying and tubing, and therefore there
should be no inherent high stress.
5. Advantage can be taken with a steel firebox to eliminate the fire hole
ring and even the foundation ring at the junction with which plates frequently
waste, due to local overheating combined with localised stress. For large
fireboxes thermic syphons can be welded in, thereby increasing the heating
surface considerably and providing support to the crown sheet to supplement
the crown staying provided.
6. Where weight is important, a steel firebox and its staying is lighter
than a copper firebox.
7. Maintenance is eased as welding makes repairs by inserting new plates,
a comparatively simple job.
8. One of the main troubles, however, with copper fireboxes is the tendency
for the tube plate to be stretched and pushed upwards by the greater linear
expansion, and particularly by the rolling of tubes. The maintenance staff
are very apt to be the cause of this, when working in a hot firebox, with
the result that the tube plate flange becomes distorted at the top and all
sorts of serious troubles result. Even in the case of large main line boilers,
this trouble has caused cracks in the top flange, particularly with fireboxes
with combustion chambers, and although various methods are adopted to protect
the copper tube plate, the steel tube plate does not suffer from these troubles
and the crown staying is far simpler. Steel boxes are more suitable for direct
crown staying.
9. The life of a steel firebox, provided water conditions are not corrosive
or low in alkalinity, is often nine or ten years, which is half the life
of the boiler. The copper firebox is unlikely to last the life of the boiler
in spite of its longer life. 10. The reduced size of stay consequent upon
the adoption of steel increases flexibility and reduces the obstruction of
the water space, but it is the design of the comparatively short water space
stays in steel which requires a very careful study, and this was considered
at length.
Discussion: C.F. Ryan (494) said that the Author, in listing the advantages
of the steel as opposed to the copper box, had said there was a marked saving
in weight, and also an advantage in delivery. If one could use a higher tensile
steel in this job, one could get a saving by reducing the thickness of the
plate. One of the disadvantages with a screwed stay would be the loss of
strength at the screwed portion, hence it might be possible to use a welded
stay. Another disadvantage would be the corrosion danger, and the speaker
was not actually aware whether there is a steel which would give better corrosion
properties. There is a rustless 40-ton steel which has a higher tensile strength
than the ordinary firebox plate, and equally good welding properties with
the ordinary plate. Provided that the steel had better corrosion resisting
properties than the existing firebox plate stecl, it occurred to the speaker
that it may possibly be a good thing to experiment. He snggested that stainless
steel might he used and hc asked if the Author would comment on the possibilities
of stainless steel fireboxes.
H. M. MacIntyre (494) said that almost 30 years ago he had to take out copper
boxes and change over to steel at the rate of about 4 to 5 per month. With
regard to maintenance, steel boxes were very easily patched, so much so that
when it came to modify numbers of boilers whicn were non-superheated, one
simply cut out a portion of the tube area and welded a new piecc in. With
regard to the thickness of the tubeplate, he agreed that 3/8in. should not
be exceeded. Copper ferrules could be used on the tubes, expanded in the
barrel followed by beading over and welding. He had nevcr thought of turning
the boiler up on its end to weld, and had nevcr filled it with water, and
he had had no complaints. He expressed surprise that no allowances were given
for the tubes in the way of staying the tube plate. He was also surprised
that the illustration did not show the hollow stays.
Vandy, W. (Paper No. 526)
The production of steel wagons. 502-31. Disc.: 531-9. plan, 5 diagrs., 26
illus.
Author was Works Manger, Shildon Wagon Works. Mass production techniques
and widespread use of welding, including development of jigs and automatic
welding machines.Illustrations include an iron ore tippler, coke wagon, hopper
coal wagon, an experimental bulk cement wagon and a bogie iron ore wagon
of the type used to Consett. Discussion: C.A. Gammon (532-3) noted that the
LMS had employed mass production techniques to manufacture timber wagons
from 1923.
T. Henry Turner (534) said that the Paper showed that the
Author had inherited a very fine tradition in Shildon. He recalled the time
when Mr. A. C. Stamer took the speaker round that works in 1930, and also
the later guidance of Mr. Thompson, Mr. Peppercorn and Mr. Smeddle; but the
man who stood out in Mr. Turners memory was Mr. Cruddas. He was a real
works engineer and the pioneer of many things which Shildon Works did before
other works considered them. His flash-butt welding was an adjunct to the
smithy, bringing the smithy technique up to date. His multiple-head oxygen
cutting was another modern way of helping the smithy. He introduced flash-butt
welding for three-link couplings and fabricated steel axlcboxes, of which
he was the pioneer, in these works which are located in the country, and
which might therefore have been backward. Instead of that Shildon enjoyed
a tradition of progress, and their workpeoplc stayed there and developed
their own methods and tools in a keenly progressive manner.
Axleboxes-On the question of Shildon axleboxes, he had one criticism
to offer, that he saw on the track too many of their doors open and coal
slack in the bearing; something needed to be done to kccp the axlebox doors
shut.
Corrosion-With regard to corrosion, it so happened that in the Shildon
works a hundred 20-ton side door opening coal hopper wagons were built about
1939, in the sloping bottoms of which were incorporated symmetrically plates
of four different steels; namely mild steel, copper-bearing steel and two
low-alloy steels. This was done in conjunction with the Iron and Steel Institute
Corrosion Committee, and a R.I.S.R.A. report on ten years of examination
of those wagons was published by the Iron and Steel Institute some
two years ago. It seemed to show that it would pay to use some lowalloy
steels.
However, the percentage corrosion reduction offered by any lowalloy steels
in thiy country or in other countries was still relatively small as compared
with stainless steels and one was therefore led to consider improved methods
of protection against corrosion.
Galvanising-Some years prior to nationalisation consideration was
given as to whether the open goods steel wagons which Mr. Cruddas pioneered
could not be taken piece by piece -and zinc coated in a hot galvanising tank,
to show the mechanical engineer as a demonstration some completely galvanised
wagons.
The civil engineer used galvanising of steel with good results as did the
marine engineer, and even the automobile engineer when he built the Land
Rover galvanised many of the exposed bits and pieces; but oddly cnough there
did not seem to be a single British Railway mechanical engineering works
which used galvanising, so it did seem that such a demonstration should be
made.
Unfortunately the disturbances caused by nationalisation killed the idea
at first, and then when it was taken up again by the late Mr. Pugson the
price of zinc soared and it became almost unobtainable. Fortunately, however,
zinc was now cheaper and obtainable once again so that tests with galvanising
of steel wagon components were again a practical possibility. Figs. 2 and
3 showed components which could almost certainly benefit by being
galvanised.
Thinning-If a component went out of service due to thinning, the thinning
was not only due to abrasion on the side which wore by friction, but also
on the other sides due to corrosion. To take, for example, an Instanter coupling,
if it were galvanised friction would soon rub away the zinc at two places,
but zinc had the property of preventing corrosion of the steel in its
neighbourhood. Normally such a coupling would go out of service through thinning
but if it were galvanised to prevent corrosion at the back, the coupling
would remain serviceable for a longer time. Metal spraying could be used
as an alternative in some cases either with zinc or with aluminium. For real
protection against the corrosion difficulty mentioned by the Author at the
beginning of the Paper, galvanising or metal spraying were better than
painting.
Bearing Metal-It would be interesting to hear from the Author whether
other Regions of British Railways were still using the former LNER carriage
and wagon bearing metal with 56 per cent tin. That particular bearing metal
was popular because of its excellent casting properties, and although mechanical
tests had shown merits in other bearing metals, the former 56-60 per cent
tin alloy was probably the easiest bearing metal to cast and so resulted
in the minimum of defective bearings in manufacture.
Ell, Samuel O. (Paper No. 527)
Developments in locomotive testing. 561-91. Disc.: 591-633; 729-34 + 4 folding
plates. 2 illus., 19 diagrs. Bibliog. .
Meeting in London at IMechE on 18 December 1953: R.C. Bond in chair
The thermodynamics of the locomotive is inseparably linked with the
mechanics of the train. It was shown how this can be accomplished in locomotive
testing in a manner both analytical and demonstrative. In describing its
development it was shown (1) how the performance and efficiency of a steam
locomotive can be expressed by a three-fold relation and by a two-fold relation
in thermo electric units, and (2) why the mass, system of locomotive and
train and its normal mode of progression must be preserved in demonstrative
analytical testing. Since the normal mode of progression is one of variable
speed, an outstanding problem has been the control of the thermodynamic factors
at variable speeds. Finding a solution in apparatus and methods which are
simple and easily applied, a full description and analysis was given of a
test on the Controlled Road Testing System. How the results of a number of
tests are coordinated was described and the paper concluded with a discussion
of the implication of the results in respect to the efficiency of the locomotive
as a mobile power plant and as a motive power unit with its associated operating
problems.
Illustrated by tests conducted with King class 6001 using controlled
road testing. On page 565: "Then, with respect to the steam rate-power relation,
it was demonstrated that this is the Willans' relation. Every student of
steam should, but usually does not, know Of the fundamental connection between
the indicated steam rate and hypothetical mean effective pressure for the
two conditions of governing by throttle and by cutoff. P.W. Willans, 60 years
ago, showed that similar relations held for the practical engine and the
distinctive curves for the two conditions are known by this name. And of
course, it applies to the steam locomotive, though one may search its literature
in vain for a mention of it": see also an Appendix
and Paper by Willans..
Discussion: Stanier (pp 591-2): said
he could not help thinking that if he could have had the advantage of some
of the information now in the possession of designers and obtained by the
careful analysis of the testing of the various thermodynamics and mechanical
parts in the construction of locomotives, he would have been much happier
in the work which he undertook. It was very interesting to see that the old
dynamometer car, the underframe of which he designed when in the drawing
office, was still running. He recalled that when he started in one of the
drawing offices he had the privilege of working in the old dynamometer car.
It was a four-wheeled vehicle with a fifth wheel for operating the mileometers,
and it originally had a laminated spring something like a buffer spring.
Mr. Pearson, who was doing experimental work, designed a spring built up
of separate plates with rollers between the plates, and that spring was in
the present dynamometer car. Therefore the work done by Mr. Pearson was still
helping in the work being carried out at Swindon. He wondered whether the
very interesting and ingenious method of obtaining the steam flow from the
tip of the blast pipe which operated a gauge on the footplate might not be
of some guidance to the footplate staff if they had to work the engine to
the degree of accuracy and speed which he Author forecasted on his test.
A thing which had puzzled him for a long time, having ridden on many engines,
was whether the right practice was to notch up as close as possible and have
a full regulator, or whether to let the gear out a bit and ease it on the
regulator. He had never been able to solve that problem himself, and it seemed
possible to find an answer. The impression he gained was that it was all
very well to have a gear which could be notched up to 10 per cent and work
at full regulator, but it put a good deal of stress on the gear, and drivers
found that it was better to work at 18 to 20 per cent and ease the regulator.
He desired personally to thank Mr. Ell for having presented the Institution
with such an excellent Paper which would be a source of interest and reference
for a number of years to come. In fact, as long as steam locomotives ran.
Mr. Cock did not think that they would run much longer, but there was still
life in them and the work done by the Author had put another period on their
life because more efficient locomotives were bound to result from it.
Meeting at Midland Hotel in Derby on 8 December 1953: Chairman:
R.S. Hall
A.J. Powell (616) said from the diagrams given in
the Paper some indication of the effect of the exhaust injector could be
deduced and it appeared to him that the use of the exhaust injector gave
an increased steam output of the boiler of about 4 to 5 per cent. As compared,
with a live steam injector, there was a fuel saving of something in the order
of 10 to 11 per cent. Were the figures typical for fairly continuous working?
Also, in that connection, he believed it had been known for the limited delivery
of the exhaust injector to impose a restriction on the maximum output during
tests on certain locomotives. Could the Author confirm and possibly say what
effect there would be on the boiler performance of having to supplement the
exhaust injector with the live steam injector?
The diagrams in the Paper were all in respect of the Great Western " King,"
and it appeared from the steam temperatures that a high superheat " King
" had been chosen. Had any significant improvement been shown in the maximum
output or in specific coal and water consumptions as compared with the original
design of " King " with moderate superheat?
The Author said that the boiler limit was governed by the amount of cxccss
air which could be brought into the firebox at high output and a figure of
15/20 per cent was mentioned. Did this hold good with most types of coal,
for instance, Welsh and Yorkshirc? Was it possible to affect this limit.
by, for instance, increasing the size of passage for secondary air through
the firebox door without sacrificing efficiency at low outputs due to too
much excess air, and also how did this tie up with the texhing on the London
Midland Region of controlled firing? An official film had been shown on
"Controlled Firing" and the fireman in that film was instructed to fire a
moderate amount of coal, to leave the door open until the slight amount of
smoke disappeared. Hc should then shut the door in stages watching the smoke
at the chimney until it clea,red and then fire again. The Author might like
to comment on that teaching.
On the point of the boiler water level being maintained to plus or minus
4- in., he thought this was a little misleading and that the Author had in
mind boiler water content in total, rather than the level indicated by the
gauge at any particular point, since no greater variation in gradient than
from 1 to 300 up to 1 to 300 down would affect the level on a moderately
sized boiler by about one and half inches. The Author, by implication in
the Paper, suggested that constant steam rate working was not strictly
practicable from the operating point of view on heavily graded roads, and
that on long banks it was necessary to increase the steam rate above the
mean. Would it be correct to suppose that such an undulating route as the
London Midland Region, Midland Division main line south of Leicester, was
not suitable for constant steam rate operation? If so, perhaps thc Author
would comment on the feasibility of going to the opposite extreme of thrashing
an engine up hill and coasting down hill to maintain as uniform a spced as
possible. Was there any significance in that figure?
In Appendix I a formula for the efficiency of a single blast pipe and chimney
was given, and putting reasonable assumptions into that formula it did appear
that the normal blast pipe at low output had an efficiency in the region
of 4 per cent and at high output of about 7 per cent. This was very much
lower than would be obtainable with any fan system where figures of 45-75
per cent were common and was an interesting example of the convenient use
of readily available waste materials for draught production in a simple device,
even though very inefficient thermodynamically for that purpose.
J.W. Caldiwell (618) said there had been many different
opinions about the Nationalisation of the Railways, and probably still were
He thought that so far as the Midlands Centrc was concerned, it had been
an unalloyed advantagc, in that, in quite a short time, three papers had
been given by men from Swindon-Mr. A. W. J. Dymond on Operating
Experiences with Two Gas Turbine Locomotive, Mr. K. J. Cook on
G. J. Churchwards Locomotive Development on the Great Western
Railway, and now Mr. Ell on Development in Locomotive
Testing. He did not think Mr. Dymond had developed A.T.C. from the
start, and Mr. Cook had confincd his Paper to what Mr. Churchward did. He
understood, however, that Mr. Ell had actually instigated and developed the
very beautiful method of testing which he had described and they were all
very grateful to him for making it public.
He had read the Paper with great interest, and one thing he would like to
ask was if the Author claimed that the variable speed method of testing was
better than the constant speed road tcst or the stationary plant test. He
could see that it was more convcnient than the constant speed road test because
it did not interfere with traffic so much: Also, it did literally demonstrate
that a locomotive could do a certain job, but apart from that, did it have
any inherent advantage over the constant spced test or the stationary test
on a fixed plant?,
Another point which was not clear was thc method of controlling the water
level in the boiler to such small limits. The Paper implied that the control
of the water level was not solely the responsibility of the engine crew,
as a system of lights was mentioned to warn the crcw when the water level
variation was approaching the limit.
In rcgard to the coal feed, the Author stated that immediately one incrcment
was removed from the scuttle, another onc was put in, in other words, it
was not dependent on time, it was only dependent upon the pressure gauge.
If that were so, why was it so important to be so particular about the actual
increments? It would not matter if a couple of buckets were tipped in at
once, the fireman would still fire at the rate dictated by the pressurc gauge.
The use of the pressure of the exhaust steam at the blast pipe tip as a criterion
of the steam production and the casy indication of the former in the locomotivc
cab and the dynamometer car by means of the air balancing dcvice was very
interesting. He wondered, however, whether the system was affected when using
the same amount of steam in two different ways, viz. high speed with early
cut-off and low speed with late cut-off.
In conclusion he thought the Author was a little unkind when he referred
to students who had never heard of the Willans law. He had heard of Willans
and his famous line, but then he was gctting old. Young people would be more
interested in the air standard cycle, and if they got as far
back in history as the Otto cycle they probably thought they
had done very well.
Mr. L. J. Brown (A.M.) asked if the tendency was for more road testing and
less static testing; would the train crews be taught a different method of
firing the locomotive, and would it entail more instruments for the footplate
crew?
R.S. Hall (619) said they had been most interested
in the facts and figures the Author had given them and remarked on the amount
of work entailed in producing them. He was a little surprised that the Author
had been able to obtain such uniform curves as shown in the diagrams because
one would expect under road conditions and other extraneous factors that
this would not be possible, however the results showed that observed points
did lie on very smooth curves.
One of our great writers-it was either John Ruskin or Robert Louis
Stevenson-prefaced one of his works with the remark that "Man's function
in life was to find out." Mr. Ell had taken that very much to heart and had
certainly done some sterling work in finding out what a locomotive could
do, getting valuable facts and figures from dynamometer car and test bed
readings and combining these with thermodynamical considerations, the results
had formed the basis of a valuable Paper which had proved very interesting,
and one which no doubt would often be consulted. Mr. Hall noticed in Fig
7 that the Author gave the chimney orifice as having an internal slope of
1 in 14. Was that the Western Region general practice? He had an idea that
the chimney shape conformed more to a cone of 1 in 6 which was the cone of
a jet of expanding steam; perhaps the Author had figures for other chimney
cones as well.
Recently a speaker (a diesel engine enthusiast) at a meeting in Derby had
mentioned that he thought the thermal efficiency of a steam locomotive did
not exceed 10 per cent. Mr. Hall had then thought that this was perhaps an
under-estimation, but from the slides shown it appeared that the statement
was correct and that in general the Western Region obtained 9 per cent thermal
efficiency constantly on long runs and as the Author's figures were very
reliable it would appear that only in exceptional circumstances would 10
per cent be obtained.
Meeting in Manchesteer held at the College of Technology on 26
January 1954: Chairman Colonel G. Rigby
R.C.S. Low (730) said that he noted from one of the slides of a King Class
locomotive on the test train that there appeared to be a loss of water from
the injector, and he wondered whether this water was metered in any way.
He also asked for further information of the Swindon Flow Meter. Reply: The
wastage noted by Mr. Low in a photograph of a test in progress was of exhaust
steam due to a leaking valve of the exhaust steam injector which was not
then in use. Water overflow is automatically metered before rejection. The
flow indicator is used by the driver to control the working of the engine
by the cut-off so that the demand made on the boiler by the cylinders remains
constant throughout. The water evaporated is obtained by direct metering
of the water injected; this rate should be constant because the rate of steam
demand is kept constant by the driver.
W. Bradley (730) said that he entirely agreed with, the Author that the greatest
economies were to be found by properly planning engine diagrams for continuous
service, and following up to ensure that speed schedules and timings were
maintained. It would be found that the great body of enginemen were behind
any attempt to keep trains in motion, for nothing was more irksome to them
than detention at signals, and nothing indeed was so expensive in all phases.
He recalled that at one depot at which he was stationed, the overall coal
consumption usually averaged around 58 to 62 lb. per mile, but on one occasion
after a period of fog, during which the mineral trains were held up for
considerable periods at signals, and then allowed to draw up slowly to the
next with heavy expenditure of steam, the coal consumption shot up to 110
lb. per mile. These facts require to be pressed home to signalmen, as well
as to diagram arrangers. It is found possible to arrange long, continuous
work diagrams for high priced alternative forms of motive power, in order
to justify the initial expenditure, we should use the steam locomotive in
the same manner. There are now available powerful steam locomotives which
are, without question, efficient mixed traffic machines. The diagrams should
be built up around them, to keep them away from locomotive depots except
for recoaling and washing out. That and keeping them moving is the way to
economical working.
Bradley also asked if it was proposed to tutor enginemen in one standard
method of operation? If so, what was that method? Would the Author advise
working the engine with fully opened regulator, and governing the output
by "notching" up the valve gear, or would it be permitted for the driver
to regulate his speed by means of the regulator? Locomotives worked in the
latter manner certainly kept in good mechanical condition longer than those
worked regularly with the full regulator opening, and there was no noticeable
difference in coal consumption. Had the Author any coal consumption figures
bearing on this subject?
Reply to Bradley :enquires about efficient methods of working the loco- motive.
The boiler produces more steam per pound of coal if the firing rate is matched
closely with the real rate of coal consumption, i.e. by what amounts to
"controlled firing" methods, but maximum boiler efficiency is obtained for
the duty required of the locomotive- when, with these firing methods, operating
conditions permit the steam demand to be steady and regular, varying little
with gradient. These conditions are also highly conducive to maximum economy
in the use of steam, but having regard to the effect of smooth running on
maintenance, the optimum or best driving method is to work at as: high a
steam chest pressure as smoothness of running permits. This rule is a better
guide than regulator position. In fact at light rates of working, full regulator
with a very short cut-off is neither economical in steam nor productive of
smooth running. On the other hand, relatively long cut-off with partial regulator
and low steam chest pressure is definitely not economical in steam. Whilst
none of this is new, it has been confirmed by both analytical tests and
observational trials of revenue earning trains over a number of years. Mr.
Fo·re questions whether the time schedules of trains running on steeply
graded lines can be calculated from the results of Controlled Road Tests
made over less steeply graded routes. To find the equivalent load on a steep
gradient to correspond to a steam rate and speed which by demonstration has
been shown to correspond to a heavier load on an easier gradient is merely
a technical calculation involving no question of principle. It is not necessary
for the test to take place over the line for which the schedule is required,
whether the line be suitable or not for this purpose, but it is essential
that the test should take place on a route where continuous steam and coal
rates can be kept for a period long enough to quantify the rates. Controlled
Road Tests epitomise, if they somewhat idealise, the economy attainable by
what is the equivalent of " controlled firing" when combined with a steady
steam demand and the efficiency attain- able by feeding steam to the cylinders
at a steady rate and at the maximum practicable steam chest pressure.
J. Fore (730-1) spoke of the ex-LMSR Class
4F 0-6-0 which had had its blastpipe and chimney redesigned to Swindon
specifications and had completed steam tests recently over the North Wales
main line. The modified draughting arrangements had raised the maximum continuous
steaming rate from about 12,000 lb. /hour obtainable with a normal engine
of this class to almost 21,000 lb.v hour. He would like to compliment Swindon
on this achievement, being but one of the many successes scored through the
careful thought and research which had been devoted to this subject over
a number of years. Commenting on the arranging of timings to give a constant
steaming rate, or as nearly constant steammg rate as possible Mr. Fore remarked
that the whole of the tests shown had been based on the London/Bristol road
of the Great Western, and he said the gradients there were nothing when compared
with the gradients encountered north of Crewe, and negligible when compared
with the gradients encountered in the Northern Division of the LMS. He doubted
whether a constant steaming-rate schedule would be practicable between, say,
Carnforth and Carlisle with the 31-mile climb to Shap followed by a similar
length. of downgrade to Carlisle where the steaming would be hardly one-third
of that needed for the climb.
Mr. Fo·re questions whether the time schedules of trains running on
steeply graded lines can be calculated from the results of Controlled Road
Tests made over less steeply graded routes. To find the equivalent load on
a steep gradient to correspond to a steam rate and speed which by demonstration
has been shown to correspond to a heavier load on an easier gradient is merely
a technical calculation involving no question of principle. It is not necessary
for the test to take place over the line for which the schedule is required,
whether the line be suitable or not for this purpose, but it is essential
that the test should take place on a route where continuous steam and coal
rates can be kept for a period long enough to quantify the rates. Controlled
Road Tests epitomise, if they somewhat idealise, the economy attainable by
what is the equivalent of " controlled firing" when combined with a steady
steam demand and the efficiency attain- able by feeding steam to the cylinders
at a steady rate and at the maximum practicable steam chest pressure.
The application of the results to such cases as were mentioned by Mr. Fore
involves the introduction of no new principle. Bearing in mind that, within
the economic conversion band of the locomotive the steam rate is not very
critical in respect to efficiency, the rate may be reduced to meet a speed
restriction, or steam may be considered as shut off altogether if this involves
reduction below the minimum rate of the economic band. Over these very routes
the LMSR in 1946-47 carried out tests; the coal and steam consumption of
the most economical runs plotted against time show a striking resemblance
to Fig 3 when interruptions imposed by practical track features are taken
into account. The same tests showed that because an engine appears to be
working heavily at slow speed on a steep rising gradient that its steam rate
is necessarily higher than the average and that when it is running at high
speed, notched up and with restricted regulator opening, that its steam rate
is necessarily lower than the average. Hence the introduction some years
before of the scheduling of trains on the steam rate system on the former
GWR and present Western Region was successful because it involved no new
principle of locomotive handling, only the best of what was already known
applied in a technical form. The system was and is as successful over those
parts of the Region which, because of their heavy grades, produce problems
at least equal in magnitude to those mentioned-by Mr. Fore.
D. Patrick (731) referred to the Author's reference
to controlling the water level to ± 1/8 in., and asked
if it had not been found difficult to obtain what were called still water
conditions, havmg regard to the way water surged, ebbed and flowed in the
firebox, and he asked what provisions were made for the actual variation
in the water level due to the changing gradients. In connection with front
ends, Mr. Patrick asked if a nozzle fitted with tips, commonly known as
"Goodfellow Tips," had been tried and with what results. Continuing, he said
that some of British Railways locomotives were fitted with diaphragm plates
like the American Master Mechamcs front end and asked how evaporation of
the boiler with diaphragm plate ends at both ends compared with .none at
all. Also, were. any tests made on the oil burning locomotives and if so
did any mterestmg information emerge on oil burning as against its counterpart,
coal fuel?
Journal No. 236
Tuplin, W.A. (Paper No. 528).
Some questions about the steam locomotive. 637-65. Disc.: 665-714: 1954,
44, 167-73. illus., 10 diagrs. 3 tables.
Most of this paper, including the
monumental, but mainly destructive commentaries by Carling, Ell and Holcroft
are considered on the Tuplin page and are not repeated here. An outsider's
(but a professional engineering outsider) view of locomotive development.
The paper is interesting in that all of Tuplin's views more widely aired
in several books and many magazine articles were subjected to scrutiny by
professional locomotive engineers (thus the response is especially interesting).
Tuplin argued that the extra weight demanded for stronger boiler plates invalidated the "advantage" of adopting higher boiler pressures. The following Tuplin criteria were subjected to Tuplinesque scrutiny by Carling:.
(a) The higher temperature of the water means higher temperatures
in all the main components and this can affect the copper firebox and copper
stays appreciably as that material begins to lose strength as the temperature
rises above about 300°F.
(b) The higher temperature and pressure of the water accelerates any chemical
action of its impurities on the boiler.
(c) The thermal stresses in critical parts of the firebox wall may be increased
by the effect of the greater thickness.
A key feature of Tuplin's paper, and one debunked by Ell was Table III best speed ranges on page 647 wherein the best speed range in terms of boiler/cylinder capacity and the best speed for valve performance were listed together with their overlap if any: there was alleged to be none for the GCR Director class, and only the range 50-59 for the King class: the latter was clearly perceived as a red flag by a bull by Ell!
Two cylinder designs were advocated as against the use of multiple cylinders: if multiple cylinders were adopted then he favoured the layout employed on the B16/2. Favoured narrow fireboxes and the absence of trailing axles. Cited Goss (this got him into a lot of trouble) to advocate the use of simple front ends as aginst multiple blastpipes and chimneys. He made a number of comments on the ergonomics of cabs and the operation of firehole doors.
Discussion: H. Holcroft (665-8) opened the
discussion and on page 666 (when well into his response) Holcroft noted that:
"In the Paper much prominence was given to thermal efficiency per se.
To the locomotive engineer, however, thermal efficiency was only one factor
of many and it had to be considered with due regard to all the others which
went towards the making of optimum power. It might well be
that in the end some sacrifice of thermal efficiency could be beneficial
in producing the most suitable motive power unit. Holcroft was highly critical
of Tuplin's assertions concerning low boiler pressures: "such engines were
amiable and reliable machines but most lethargic" Holcroft was also highly
critical of Tuplin's observations on firing methods, on superheaters, and
on lost motion in valve gear due to excesssive clearances (and cited his
own measurements to show that was not the case).
C.C.H. Wade (668) commented on firing techniques and the limits of
endurance for firemen.
R.G. da Costa (668-71) was highly critical of Tuplin's observations
on superheating, and in particular Tuplin's attempt to relate grate area
to superheater surface and temperature; Tuplin's interpretation of Goss's
observations on unconventional valve gear which da Costa considered had been
made prior to what da Costa stated were "substantial improvements" in the
design of valve gear, especially in poppet valves.
S.O. Ell (671-4) see Tuplin page.
Pelham Maitland (674) recorded that in a large number of instances
where the boiler pressure had been raised there had been an immediate and,
in aggregate, appreciable saving in coal consumption. On firing engines with
wide fireboxes, the technique of firing to the four corners of the firebox
and little elsewhere produced one outstanding feature. It tended to the more
thorough combustion of the coal than otherwise would be possible, because
the draught did not tear the fire to anything like the same extent as with
a narrow firebox. That was a feature on which he would like the Author's
comments-the tearing of the fire in a narrow firebox as compared with a wide
firebox.
A. Hood (674-6) noted that Tuplin queried whether boiler designers
set themselves targets regarding weight per unit of heating surface. So far
as the private builder is concerned the answer was an unqualified affirmative
inasmuch as the weight limitations imposed by the clients' specification
set the target. Only those closely acquainted with the subject appreciate
fully what these limitations mean, particularly when restrictions are placed
on the. weight per foot run of wheel base as well as on axle loading. In
the remarks on fireboxes Tuplin made no comment on firebox volume: it has
been argued that much of the merit of the narrow box is derived from the
ratio of volume to grate area being good, and the more general adoption of
the combustion chamber seems to substantiate this. In fact it has been claimed
that the narrow box is practically the ideal shape when dealing with oil-fired
locomotives.
With regard to the comparisons of boiler weights, as given in Table 1, it may be suggested that a much more equitable basis of comparison might be to make this in terms of evaporation per hour from the various boilers. This would bring into play the division of the heating surface between the firebox and tubes. Such a comparison might be made either on the basis of any agreed rate of evaporation from the firebox and tubes or preferably on the basis of the recently published data on locomotive testing issued by British Railways.
The comparisons. made in the Paper are only fair if the locomotives are designed to the same ratios of fireboxes and tube surface. In a recent locomotive built in this country for overseas the total evaporative heating surface is in fact less than in a previous design, and the tube heating surface is some 4% less, yet the new design has permitted an increase of 40% in the firebox heating surface.
The concepts of "nominal speed," "specific speed" and " specific. effort" are highly interesting, but whether there will be general agreement with the conclusions which Tuplin derives from his analysis is open to question. Nevertheless, the argument put forward is worthy of close study.
There is probably no more debatable point in locomotive design than front end proportions, and also nothing which can so influence the performance of the locomotive in service, yet it would still seem that the only guide is experience based on previous designs, for despite the fact that the American Master Mechanics' proportions have been known for many years, it would seem that even in the USA there was nothing really standardised, at least tliat is the conclusion arrived at after studying the results of the front end experiments made in the University of Illinois, and Johnson seems to confirm this in his book on the Steam Locomotive.
While the Author's criticism of the 4-6-2 type on the basis of weight transfer may, perhaps, bear analysis for locomotives on British Railways, it cannot be applied to locomotives for railways where the permissible axle load is a limiting factor. Would the Author. faced with the problem of providing for a large boiler on a passenger locomotive, prefer to use a 4-8-0 with all it involves in the way of extra rods and resistance in preference to a 4-6-2 if the 6-coupled engine gives all the ,adhesion necessary? , As regards mechanisms one can readily agree with Dr. Tuplin when he says" the less of it the better," so why not go all the way and adopt servo motors which would put the steam locomotive driver on a par with his opposite number on other forms of power? .
The Author had referred to ash chutes for smokeboxes. Two past applications of this idea sprang to mind. Paget's 2-6-2 engine of 1907 had used such a chute, sealed at the top by a simple flat-seated plug held by its own weight in the top of the chute and with a long-lifting handle. Even simpler was the device used by F. W. Webb on his" Precedent" and 3-cylinder compound passenger engines, consisting of a chute tapering down to a rectangular hole about 6 in.x 2 in. quite open to the atmosphere! No attempt at sealing was made, but the front plate of the hopper was extended some inches below the back plate and turned over to give a crude ejector action due to the air stream when running forwards. He was not aware of any complaints of the steaming of the" Precedents," but would be reluctant to see such a device applied to modern locomotives!
He felt he must join issue with the Author on the subject of regulator operating mechanism. Whatever -the torque might be on the shaft to operate the regulator, the pull at the cab to overcome it would, of course, be the same if the mechanical advantage of tire existing and proposed linkages were the same. However, the weight of the operating rods alone on the" Britannia" boiler was of the order of 70 lb., and in view of the damage caused to them by cleaners standing on them, etc., he did not see that they could be lightened satisfactorily. Did the Author seriously suggest that the direct pull necessary to a~celerate this mass in opening the regulator would permit anything approaching the present sensitivity? He thought the Author should be copdemned to an eight-hour shift shunting with an .engine so fitted! In conclusion, he felt that drivers would rebel at the Author's suggestion to bring the cab window back close to where they sat. One thing that was very necessary in case of emergency was complete freedom of movement in the cab, and criticisms of the BR standard cab layout which had been voiced dealt with the driver's sense of being" boxed in " by the grouping of controls round him. With the proposed arrangement, the driver would be risking his skull even to tie his bootlaces!
Mr. P. R. Saunders (678-9) wrote that the Author pointed out that a 4-6-0 locomotive, particularly one with a high drawbar, would be better in some circumstances, such as starting on an up gradient or on an irregular track, than a 4-6-2 of similar nominal adhesion. The implication of this part of his Paper was, he assumed, that it was sometimes preferable on this account, to build a 4-6-0 rather than a 4-6-2, both engines having the same weight for adhesion. He would suggest, however, that 4-6-2's were only built when it was absolutely necessary from a consideration of the work required of the locomotive in other circumstances. The 4-6-2, with a larger firebox and boiler, would have a superior performance at speed, when maximum adhesion was not required, and may yet have a greater availability. In any case, Professor Tuplin's calculation of the weight transfer that took place would appear to be in some error. Since the coupled wheels were separately sprung, and the trailing axle had greater loading than the leading axle, this weight distribution among the coupled wheels exerted a levelling moment on the frame which was neglected when only the overall transfer of weight from the bogie wheels was considered. A calculation, taking that into account, showed that the transfer from idle to coupled wheels for a BR Class 5, 4-6-0 when the drawbar pull was 12 tons at 3½ ft. above" rail level was less than 1¾ tons, rather than 2½ tons.
W.O. Skeat (679-81 written communication) see Tuplin page
M.A. Henstock (693) argued that the reserve available with higher pressures was appreciated by the footplate crews; he noted that the LMS used nickel steel for some its boiler plates to reduce weight; he commented on eddy currents above the brick arch; and noted the problem associated with short connecting rods: heated bearings and crosshead wear. He did not understand the criticism about the" Patriots" and the" Royal Scots," they certainly have the same wheel diameter and cylinder sizes, but the tractive efforts were far from comparable, the first being 26,520 lb. and the latter 33,150 lb. This seemed a very big difference by which to compare a locomotive. The L.M. Region 2-6-0 Class 5, parallel boiler engine with a pressure of 180 lb./sq. in. and tractive effort of 26,580 lb. could be compared with the 2-6-0 Taper Bqiler Class 5 which bad a tractive effort of 26,288 lb., these two locomotives were, in his opinion, far more comparable to bring out the points that the Author was trying to make. Regarding the diagram showing the fire hole door, as he did not understand how it worked he asked if the Author would be good enough to give an explanation.The inward opening door was not a new idea. All the former L & Y Rly. engines had inward opening" flap" doors and one of the main disadvantages was the frequent renewal of this type of flap which burnt away very rapidly.
The diagrams of the regulator operating rod reminded him of what all designers should avoid, a "one view" scheme. The arrangement shQwnin the elevation looked no doubt feasible, but if the plan view of the boiler and rod had been shown a different picture would present itself, due to the rod having to pass the widest part of the firebox and 'be straight in the plan, t~e shaft at the multiple valve header would have to be extended considerably to line up the lever with the operating rod; this overhang was very undesirable on account of wear taking place and causing the gland packing to leak even more than at present.
The load required to open the pilot valve was 250 pounds and by the existing arrangement there was 'no chance of the rods being moved by anyone or anything from outside the cab.
If the Author's scheme could even be adopted, the chances were that this could result in the regulator being opened other than by using the handle in the cab, which would be very undesirable, especially when the engine was being serviced at the sheds, due to the possibility of the regulator being opened by some unauthorised person, cleaner, etc.
The Author unfortunately had not given anything concrete on which the designer could base a design for the smokebox; the diagram of smokebox proportions was like most, it fell short of giving the blast pipe cap diameter, or anything on which to base it for a given locomotive, the distance from the tubeplate and also the height below the centre line of the smokebox; these were the figures the designer had to search for, and how elusive they were.
D.R. Carling (694-8) see Tuplin page.
W.G.F. Thorley (698-9) noted that Tuplin stated that the object of superheating was to ensure that, despite the drop in temperature of the steam as it expanded in the cylinder, it did not become saturated. Could it not be said also that the superheater provided also a valuable addition to boiler steaming capacity inasmuch as the volume of steam was increased by its use? It would be recalled that the first two "Princess" class Pacific locomotives of the former LMS Railway had 32-element superheaters fitted in place of the original 16-element apparatus after only a short period of service, and the steaming was improved thereby. The Author had said in the discussion that the firebox volume was increased at the same time as the additional superheating surface was provided and therefore the value of the latter could not be assessed accurately, but in this connection it was pointed out that the number of elements had been increased without increase of firebox volume in both the Classes 5MT and 5XP locomotives of the same railway, as 'compared with the original arrangement and the steaming had been improved. The superheater had the advantage that, provided the flue tubes were kept reasonably clean, its efficiency remained unimpaired as the boiler scaled up internally; also it was sometimes able to evaporate water during periods of priming, which would be carried over into the cylinders of a saturated engine.
The Author recommended a 3-cylinder engine having the inside mechanism as readily accessible as that of the two outside cylinders and the B16/2 4-6-0 Class of the former LNER was instanced as an engine which nearly gave the desired feature of being able to be prepared without the use of a pit. It appeared, however, that in these circumstances the driver would have to pass between the trailing bogie wheels and the leading coupled wheels to gain access to some of the inside oiling points and this was a practice which could not be officially countenanced.
Mr. Thorley considered that the Western Region practice of lifting the flap plate between the application of each shovelful of coal, as mentioned under "Firebox" in the Paper, was brought about more by force of circumstances rather than by any conviction of the enginemen that it was the correct thing to do. Whilst such an attitude of mind on the part of the latter was a very good thing to encourage, the fact remained that if an engine would steam freely with the flap remaining down between consecutive shovelsful, then the flap remained down.
Meeting in Glasgow, 26 January 1954: A. Hood:
(704-5): noted that the first Merchant Navy class boiler was designed
and built in Glasgow, and at the request of the customer a second edition
of the boiler was designed and constructed which proved to be approximately
2 tons lighter than its predecessor. This was a typical example of the designer's
art which reduced the weight of the boiler yet maintained its original output.
J. Campbell (705) emphasised that higher boiler pressures provided "ample
reserve capacity. Considered that the inertia effect in valve gears noted
by Tuplin could be used as an argument against conjugated valve gears. E.F.
Clark (706-7) mentioned that comparison was seldom made between
steam locomotives and stationary reciprocating steam engines.
In this connection it was interesting to recall that on the
question of high superheat there were very few cases of steam temperatures
over 600°F. being used in stationary engines, especially those with
cast iron cylinders. The locomotive engineer tended to look at the performance
of the locomotive from the point of view of tractive effort, while on the
other hand, although for stationary engines conditions were different, engineers
considering them looked at their performance much more from the point of
view of steam flow and power output. On the question of eliminating unnecessary
mechanism, he suggested that exhaust valves could be cut out quite easily
by the adoption of the Uniflow system. He said that he thought all locomotives
would benefit enormously when rolling stock was fitted with roller bearings
and rail joints were eliminated by track welding. During a recent visit to
Germany when riding on a train which was admittedly hauled by an electric
locomotive, but on which the whole of the stock was fitted with roller bearings,
he had been most surprised to find that when the speed of the train had been
reduced to a walking pace, the whole train rolled on for a surprising distance.
He was quite sure that power was no being applied and this rolling on could
not be obtained with stock fitted with plain bearings. It was said that there
was no lessening of tractional resistance when roller bearings were used
over about 25 m.p.h., yet all trains had to be accelerated from standstill
to this speed. He thought there was a strong case for remembering that all
locomotives would benefit greatly when all stock was fitted with roller bearing
axleboxes.
N. McKillop (707-8) With regard to the statement made by the Author that
there were no means of comparing lower pressure boilers with higher pressure
ones, McKillop said he was of the opinion there was a very good means of
comparison. He believed he was right in saying that the first Gresley Pacific
had a low pressure boiler and that eventually high pressure boilers were
adopted, and the difference in performance was fantastic; very much less
coal was burned and the mileage between shop overhauls increased from something
like 60,000 miles to 102,000 miles in certain cases, which was due, in his
opinion, to the high pressure boiler With regard to wide and narrow fireboxes
and fallen brick arches McKillop asked if the Author did not agree that wide
fireboxes were an advantage in the event of the brick arch falling. He also
said there was no difficulty in maintaining steam with the wide firebox.He
said the Author had not mentioned anything about the combustion chamber Gresley
introduced to the Pacific engine. With regard to piston valves, McKillop
said that on the indicator diagram the sharp corners were produced by large
poppet valves opening instantaneously by cam gears and he asked if the Author
thought there would be an improvement by the operation of piston valves by
cam gears. He said he was rather surprised to find that Professor Tuplin
thought the efficiency of operation of a locomotive fell when the engine
was taken above 15 per cent cut-off. In practice it was a fact that very
high efficiency of the Gresley valve gear could be obtained with much higher
cut-off. With regard to window design, which was very important, McKillop
suggested placing the glass at the rear of the tunnel instead of at the front.
He said it was surprising that Professor Tuplin had criticised the throttle
operation on the engine, because he must know that the throttle operation
of a locomotive was a very vital thing to a driver. The driver, going at
high speed, must get a fine adjustment of the throttle, and if he had the
assistance of a steam-chest pressure gauge it was necessary that he ran a
distance with the throttle so adjusted, as he could make it fluctuate between,
not 25 lb. or 50 lb. of pressure, but 1 lb. of pressure. He said the device
introduced into the throttle rod was done to give rigidity and putting the
brake handle where the Author suggested reminded him that on one occasion
the little window, where he suggested putting the brake handle, was smashed
by a passing train. It was a highly dangerous practice to put any apparatus
outside a fast moving engine for a driver to put his hand on. He thought
the operation of the firedoor by the driver was fantastic. He asked if it
was not the case that Gresley introduced the combustion chamber on the Pacific
to prevent the tubes warping, as it was found that the tubes were liable
to warp and leak very badly, and a short rigid type of boiler tube would
reduce such leakage.
A.C.D. Malcolm 708) said he thought the Author would agree that the
trailing truck helped to keep the engine on the rails, which had been proved
on at least two classes of engine.He said he thought it was better to have
a steady back end and that Mr. Hood had a very strong point there, and he
asked if the Author thought the fitting of a Cartazzi truck justifiable,
as a trailing truck improved the riding of an engine.
D. MacAulay (708) mentioned Cartazzi slides
and firedcors. In his experience in India the Cartazzi slide slid so much
that the engine used to leave the track. With regard to firedoors, the standard
design of firedoor was a scoop turning inwards and connected to a handle
by a trigger. This was also in use on the same Indian Railway. The fireman
had to shovel each shovelful of coal with one hand and work the scoop with
the other, and he kept a very constant steam pressure in the boiler.
Meeting in Newcastle-on-Tyne, 24 February
1954.
F. Johnson (712) asked the Author to comment on
the fact that it was not so many years since all boilers had narrow fireboxes
tending to keep the cylinders small, making it easier to increase power by
raising the boiler pressure. He pointed out that it must not be forgotten
in connection with weights that with an increase of 15 per cent in the boiler
capacity, to a boiler of the same weight, the lower pressure would call for
an increase in the weight of water. If the boiler pressure were increased
with the same size cylinder there should be an increase in the heating surface
and grate area if the same power were expected from the locomotive. If the
plates were merely thickened the same amount of coal would be burnt in the
firebox and the same horse power created. He said that he thought that a
greater superheater area was necessary for a locomotive which ran on a very
short cut-off and he asked the Author to comment on this point. On the question
of the transfer of weight with advantage to trailing bogies Mr. Johnson said
that in his opinion the whole of the weight would not be taken by the trailing
bogie. It would only be a portion of the weight. In commenting upon the regulator
mechanism Mr. Johnson stated that so far as he was aware the regulator handle
was often fitted with a trigger and locking ratchet and there should not
be any necessity for an allowance for expansion as the regulator was only
used when the boiler was in steam. In reply to Mr. Johnson the Author
stated that he did not see how the firebox need control cylinder sizes. If
big cylinders were wanted, the frame could be set in at the front end, and
then the outside cylinders could be 25 inches in diameter if the connecting
rods were placed against the wheel-bosses. When the size of the boiler and
the speed-range for maximum power have been decided, the nominal tractive
effort for highest cylinder efficiency in that range can be determined. The
next step was to select the largest convenient cylinder volume and then to
use the conventional nominal tractive effort formula backwards to find what
pressure had to be provided to produce the desired nominal tractive effort
in those cylinders. If only two cylinders were used to get the nominal tractive
effort, the pressure might work out at 250 lb. per sq. in. as in the Class
7 Pacifies, whereas three cylinders would give the same result with about
185 lb. per sq. in. The Author said that boiler power is not determined by
steam pressure but by grate-area and heating surfaces. It is true that a
larger boiler holds more water and so the estimate of the boiler power possible
within a given weight is not correctly based on empty weights of boilers
As Mr. Johnson said, this fact reduces the possible gain in power/weight
ratio from reduction of boiler pressure. The Author agreed that the higher
the expansion ratio the higher the minimum desirable superheat, but added
that shortening the cut-off below about 18 per cent does not raise the expansion
ratio. He added that even the small superheaters used on the GW were evidently
adequate for short cut-off working, at least with good maintenance.On the
question of weight transfer the Author said that even if the springs of the
rear truck and the preceding axle are equalised, the drawbar pull still transfers
some weight on to the rear truck and therefore off the other wheels some
of which may be driving wheels. If there is no rear truck, weight cannot
be taken off the driving wheels by the drawbar pull, ,and so a 4-6-0 has
some advantage in this respect over a 4-6-2. Regarding Mr. Johnson' s
observations on the regulator rod mechanism the Author said that this was
a good point. As expansion was small, the difficulty could in any case be
got over by putting a locking trigger at the back end .
C.H. Swan (712) said that he had listened with interest to Professor
Tuplin's remarks on the B.16 Class short connecting rod and from personal
experience he knew that the great disadvantage was the short life of the
little-end bushes; he suggested that the little ends should be fitted with
roller bearings. In regard to the transfer of weight there was another factor
to be taken into consideration. From the enginemen's point of view a Pacific
is a much better riding engine than a 4-6-0 and from the maintenance angle
the lateral wear on the trailing boxes is not normally so great on Pacifies.
Mr. Swan said that a number of the uggestions made by Professor Tuplin were
obviously very good as they seemed to adhere to former NE practice such as
the Blades firehole door which hinged inwards from the top and closed with
its own· weight, and there were the former NE type windows which opened
inwards. The Automatic Train Control device mentioned by Professor Tuplin
resembled the handle of the Ravens Fog Signalling apparatus which did away
with the necessity for fog signalmen between Shaftholme and Berwick. The
former NE vacuum handles could be reached from the window
Mr. Meicher (713.) asked if it were not possible for the therma efficiency
of the locomotive to be increased by devoting further study to the volume
of the smokebox.
Mr. Sadler (713) asked if Professor Tuplin could offer any explanation for
the apparent reluctance to accept GW practice pointing out that. Gresley
had to change a design after twenty years to fit with Churchward's design.
Had it anything to do with boiler pressure?
De Sousa, C.H. (Paper No. 529)
The design of Indian Railways passenger coaching stock for greater comfort.
715-24.
The principal conditions which militated against comfortable travel
in India were: climate, dust, noise, inadequate accommodation and lack of
amenities,, and by implication the misuse of such amenities, notably wash
basins and lavatories. The author considered that insufficient attention
had been paid to the Indian's wish to sit with their feet tucked up.