Journal Institution of Locomotive
Engineers
Volume 35 (1945)
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Journal No. 183
Clarke, C.W. (Paper 450)
Technology of the heat treatment of steel. 3-29. Disc.: 30-8.
.Meeting of Western Branch of the Indian and Eastern Centre held at
Bombay on 17 December 1943: Mr. H.P. Renwick occupied the Chair.
Indian paper: problem arose during WW2 that there were an inadequate number
of plants capable of heat treating steel. The. object of heat treating steel
is heat to improve its physical and mechanical propaerties. Treatments include
Sanford, D.W. (Paper 451).
The relationship between smokebox and boiler proportions. 40-53. Disc. :
53-76. 5 diagrs., 2 tables.
Third Ordinary General Meeting held at Institution of Mechanical
Engineers, London, on Thursday, 30 November 1944, at 5.30 p.m.: Mr. W. S.
Graff-Baker, President of the Institution, occupying the chair. Repeated
at First General Meeting (Session 1944-45) of the Birmingham Centre held
at the Midland Hotel, Derby, on Wednesday, 31 January 1945, at 7.30 p.m.:
chair being taken by Mr. E.S. Cox.
Attempted to find a relationship between the proportions of the chimney and
blast pipe on the one hand, and the boiler proportions on the other. The
factors involved were many and variable, and it was impossible to arrive
at suitable dimensions solely by calculation. The final adjustment still
depended on trial and error: nevertheless, theory was of considerable help
in enabling the designer to avoid major errors, and was also of considerable
assistance towards a correct interpretation of eflects which are observed
during actual trials.
Based on precis containd in Locomotive
Mag., 1945, 51, 42-3. The blast pipe and chimney have two
functions to perform: to eject into the atmposphere all the products of
ccombustion produced in order to obtain a given power output and to obtain
a vacuum in the smokebox to draw the reuired amount of air or gas through
the grate and tubes. The problem confronting the designer is to fulfil both
these requirements with the least possible exhaust pipe pressure. If the
problem. to be faced were merely the ejecting of a given volume of gas per
unit of time, it is clear that the larger the diameter of the chimney and
the blast pipe nozzle the better, because the larger the chimney the less
energy is. expended in ex- hausting the mixture of escaping steam and gases.
However, to provide an effective draught a sufficient vacuum must be created
in the smokebox to ,overcome the, resistance of the boiler and it is this
consideration that determines the upper limit of the chimney diameter, and
also that of the blast pipe orifice.
The resistance of the boiler is made up of the sum of the resistances offered
by the ash pan, firebed, firebox, and the tubes to the passage of the combustion
air. The greater these resistances the greater must also be the degree of
rarification in the smokebox. The size of the chim- ney, that is, its diameter,
and through that the diameter of the exhaust nozzle, determine the vacuum
obtainable. The diameter of the chimney governs the velocity with which the
smokebox gases are ejected, which must be such that the velocity of egress
equals the velocity with which gases outside the smokebox would rush down
the chimney under the influence of the vacuum created within. the smokebox,
This is the sImple and approximate method of stating the case. While computations
can be made to establish gas velocities for a given vacuum, they are
unfortunately not applicable in practice, largely due to the fact that gas
velocities are not constant and that the jet of exhaust steam has a greater
velocity at its centre or core than at the sides.
This is of interest and importance, and explains why all recent development
work undertaken with the idea of improving the efficiency of the jet of steam
has been centred upon finding means for splitting the jet or usmg a multiplicity
of jets in order to make use of the high velocity of the centre portion.
The much larger engines now used which necessarily require boilers of high
evaporative capabilities has forced attention to the exhaust steam passages
and the design of the blast pipe and chimney. In the interests of cylinder
efficiency back pressure must be low, while on the other hand large boilers
offer relatively high resistances to the gas flow, for though a large grate
may have a somewhat low resistance due to a thinner fire, the gas flow per
tube may be, and in fact is high, this latter being brought about because
in the case of large boilers the net gas area through the barrel is and must
be low in proportion to, that of the firegrate, for the reason that it is
usually easier to find room for a large grate than it is to provide a large
barrel. diameter.
Discussion: O.V.S. Bulleid (53-5) was highly critical of he use of
a mercury U-tube for measuring smokebox vacuum and advocated the Cambridge
Instrument developed with Gresley. Described his WW2 experiment of fitting
a locomotive with two separate chimneys in an attempt to break-up the exhaust
trail. He advocated larger chimneys with a 7 to 1 ratio rather than the more
usual 3 to 1 ratio. and cited work on Lord Nelson class chimneys H.I. Andrews
(55-6) commented upon smokebox efficiency and its measurement; E.S. Cox (56-9)
thought that chimneys might "certainly be made larger than at present" and
noted that the Duchess Pacific with double chimneys were working at nearly
the Author's suggested criteria. He also described the evolution of tube
sizes in the Jubilee class boilers which attained 1 7/8 inch with a double
chimney; W.F. McDermid (59) noted that Great Eastern locomotives
working on Brentwood bank with a full regulator had a clear exhaust when
notched up and Sanford noted that the thickness of the fire was essential
for good steaming; E.C. Poultney (59-60);
T. Henry Turner (60) referred to statement that “
Theory may be likened to a candle and experience to the sunlight,” said
it would be desirable to know something more about what had been found by
experiment, and therefore he would like to ask the Author, with the aid of
the Research Department or the Institution staff, to add to the Paper a
bibliography, and line sketches of typical blast systems. There were so many
that it might be difficult to choose representative ones, but he felt that
the Institution should be able to present some historical background to a
Paper of this kind. He would like to ask what had been found with regard
to the need for circularity, and to what extent it was possible to depart
from circular chimney or nozzle without getting into trouble. If it were
possible to depart from it, then it would be very simple experimentally-and
possibly the testing plant at Rugby would undertake it later-to arrange a
locomotive with manual control of the size of the nozzle and of the chimney.
If it were possible to depart from complete circularity an arrangement of
the type shown in the accompanying sketch (Fig. 5) might be tried. That would
be simple with the chimney, but not so simple with the blast nozzle. He would
like to ask what was known with regard to the need for circularity of locomotive
chimneys and blast nozzles and whether tests had been carried out with
manually-controlled variable ones; H. Holcroft (61-2) asked why quite small
leaks into the smokebox had such a major influence on steaming and Sanford
in reply could give no sound reason; W.F. McDermid (62) noted
his own papers in Journals No. 108 and 112 (1932/3);
W.H. Hutchinson (62-3) said Holcroft had already referred
to the point which he desired to make. When chimneys were mentioned he thought
of the old Belgian 2-4-2 locomotives with the square chimney. It was a hideous
object. He did not know whether it was actually square inside, but it looked
rather like a brickworks outside.
The Great Western Railway always had the reputation of being in the first
rank for front end design, but many of their engines designed by Mr. Churchward
had rather small chimneys, and it was only in comparatively recent times
that a chimney of relatively large dimensions had been fitted. Mr. Holcroft,
he believed, had had some experience on the G.W.R. in the early days, and
might be able to give some information about that. He was thinking in particular
of the Mogul engines, which, in the early days at any rate, had a chimney
of very small diameter, but apparently did not suffer from any lack of
steam.
The calculations in the Paper were interesting, but it would take a long
time to go through them and work out the figures for all the different classes
of locomotive on a railway. He did not know whether anybody could be persuaded
to do so; it might provide some shocks, and make people think a little more
about front end design.
H. Holcroft, replying to Mr. Hutchinson’s question, confirmed
that he had been one of those concerned in setting out the standard chimneys
on the G.W.R., the proportions of which were based in the first place on
GOSS’Sf ormula. They were then tried out on the road and subsequently
modified to suit the conditions on the Great Western line.
E. W. Selby, referring to the Belgian engines with the square chimney,
said that the chimney was square inside as well as out, and they had a square
blast pipe with two flaps at the side to provide a variable blast.
The President (Mr. W. S. Graff-Baker) said he had listened with great interest
to a Paper and discussion on a subject of which he had to confess tcommented
upon the very small chimneys fitted to some GWR locomotives, notably the
43XX class - Holcroft replied that these were designed using the Goss formula;
Hutchinson also refered to the square Belgian chimneys which E.W. Selby noted
were square inside and Sanford noted that such chimneys were sound as there
was a great surface area for a given cross-section.
Presented at Derby on 31 January 1945 with E.S. Cox as Chairman (remarks
69-71); T. Baldwin (71); J.W. Caldwell (71-2) noted the
power loss in exhaust due to back pressure; G.F. Horne (72)
noted that the US 2-8-0s combined good smokebox vacuum with soft
exhaust; E. Durnford noted Chapelon's use of large steam passages; E. Sharp
(73) observed that smokebox vacuum varied with different rates of working;
D.W. Peacock (74)
Meeting at Derby, on 31st January, 1945. 69
The convener and acting Secretary being Mr. E. Durnford, who said
that the last occasion that that Centre of the Institution-met was on the
15th March, 1939, in that hotel, to hear a Paper on “ Progress in the
Iron Foundry,” and since then there had been no meeting of that or any
other local Centre. In the time which had elapsed since then, their Chairman,
1,ieut.- Col. G. S. Bellamy, had moved permanently to Scotland, and their
Hon. Secretary, Mr. F. J. Pepper, had gone with him. Their Vice- Chairman,
Col. H. Rudgard, had gone south to London, and the Committee by the terms
of its appointment no longer existed, because it was retired formally as
from May 3Ist, 1941. A temporary committee, consisting of the following members
of the old committee, Messrs. Bailey, Spital and Hall (representing Birmingham),
and Larkin, Rankin and Sanford (representing Derby), with the addition of
Messrs. Cox; Caldwell and Durnford; Mr. Cox acting as Chairman and Mr. Caldwell
as Hon. Sec. The Chairman then introduced Mr. D. W. Sanford, who read his
Paper, entitled “ The Relationship Between Smokehox and Boiler Proportions.
”
Journal No. 184
Meeting in London, 22nd February, 1945. 83-4
The President announced with the greatest regret the decease of Mr.
A. C. Carr, V.D., which took place at his home in London on January 25th,
1945. Mr. Carr, who became a member of the Institution in 1917, was elected
a Member of Council in 1925, and was President for the Session 1935-36. The
members stood in silence for a few momepts as a token of respect. The minutes
of the meeting held on 25th January, 1945, were read by the Secretary, and
were confirmed and signed as correct. The following applicants for membership
were duly elected :
The President said it was necessary for the Corporate Members present to
choose two or three scrutineers for the purposes of the ballot to be held
at the Annual General Meeting for the election of Members of Council to fill
the vacancies and invited nominations. None being forthcoming, he suggested
the appointment of Mr. Selby and Mr. Lynes, on the understanding that, if
one of these gentlemen were unable to attend, the other might co-opt someone
to take his place. This was agreed to.
Collins, A.F. (Paper 452)
Power-operated doors for railway rolling stock. 84-104. Disc. 104-9.
Fourth Ordinary General Meeting held at the Institution of Mechanical
Engineers, London on Thursday, 22 February 1945, at 5.30 p.m., Mr. W.S.
Graff-Baker, President of the Institution, occupying the chair.
The President, in introducing the reader said that Mr. Collins had been
associated with the development of door mechanisms for the London Passenger
Transport Board’s rolling stock since the first practica1 doors were
put into service, which meant going back to 1918, from a design point of
view. He therefore knew a great deal about his subject, a fact which would
be confirmed by his Paper. Anyone who wanted a practical demonstration of
his knowledge had only to take a Tube train.
When the London 'Transport tube lines were first built it was considered
sufficient to provide a gangway at each car end with a door in the car body
giving on to this gangway which was enclosed by collapsible steel gates operated
by a gateman. A crew for a six-car train consisted of a driver and five gateinen,
one situated at each pair of gangways, the rear one acting as guard. This
arrangement under crowded rush hour conditions interfered with passenger
movement, whilst the number of staff was disproportionate to the number
of passengers carried. The problem became most acute on the end cars which
had one gangway only. When rolling stock was constructed in 1917 for the
Central Line extension from Wood Lane to Ealing Broadway, the end cars were
designed with an additional doorway with a hinged door, arranged to be closed
by means of door checks and to be held locked in the closed position until
released by the guard. The London Electric Railway was experimenting on similar
lines with cars built to this pattern: the stock jointly owned by the London
Electric Railway and LMS for operating the Watford service had cars fitted
with centre doorways of controlled by the guard. Besides not being
unsuccessful mechanically, it did not solve the excessive number of staff
employed. Thc London Electric Railway put into service in 1920 forty new
trailer cars fitted with pneumatically-operated doors at the middle and at
each end, and converted, to run with these cars, twenty motor cars fitted
with double centre doorways and an end vestibule doorway for the guard. Two
guards were employed, each controlling half the train doors from the appropriate
motor car. The success of this arrangement was apparent.
Mr. W. A. Agnew (Past President), who had been engaged in work on air-operated
doors at an even earlier period than the Author, commented on the fact that
the earlier types of door equipment were not mentioned in the Paper, and
said that the first use of air-operated doors in this country was on the
District Railway in 1905, when over 400 cars were fitted with air-operated
sliding doors, and also had centre doors. It was true that those doors had
a very brief existence; the public did not like them, and even the comic
Press made fun of them. Although everything possible was done to try to make
those doors operate satisfactorily, it was found that they were of such a
design as to prevent any real improvement being effected.
The construction was very simple-not nearly so elaborate as those since devised
by the Author-and consisted merely of a little engine fitted on the top of
each door, something like a bicycle inflator. Air was usedYrom the compressed
air system for the brakes, and was admitted into those little cylinders by
means of valves. Between each carriage there had to be a gateman who was
perched precariously on the buffers to operate the valves. In that position
he could not see very well when to close the doors, which led to some little
difficulty with the passengers.
He believed that those doors lasted for only about eighteen months, but they
were a gallant effort to introduce power operation. After that the doors
were operated by hand, and continued to be so until recently. The operating
manager was glad to reduce the number of gatemen, and that had been one ot
the most powerful reasons for fitting air-operated doors on the Tube railways;
it had been possible to make great economies after the last war by fitting
air-operated doors and so reducing the staff, but the system adopted, of
course, was very different from that tried out in 1905.
He would like to ask what reducing valve the Author found to be the best
in order to reduce the main line pressure to that used on the doors. The
Author mentioned that the rubber sensitive edge of the doors, which used
to be fitted with a japanned leather surface, now had a plain rubber surface.
The original intention of the japanned leather was not merely to allow skirts
to be withdrawn if they were caught in the door but to prevent water getting
in from the curved top of the door; it was found that the polished surface
readily shed the water. Reference was made in the Paper to trains equipped
with purely pneumatic control for the doors. That apparatus in fact worked
very well, and he would suggest to those requiring power-operated doors on
short trains that that was an attractive way of dealing with the problem.
Mr. H. Holcroft congratulated the Author on compressing a great deal of valuable
information into a comparatively short Paper, a model of its kind. Speaking
as an onlooker, he remarked that what struck him about the apparatus was
the absence of any anti-friction arrangements. There was a slide at the top
of the door which would, one would imagine, create a certain amount of friction.
He did not know whether ball- or roller-bearings were provided on the rollers
carrying the door, but any reduction in friction would of course economise
in air by requiring very much less pressure to work the doors.
Apparently there had not been much experience so far with the
individually-operated doors where the passenger had to press a pushI button.
He did not know whether there was a push-button outside the car as well as
inside, but it seemed to him there might be some difficulty in passengers
who were strange to the method obtaining entrance to the train if they did
not quickly grasp how to open the doors, more so at night on open sections
of the line.
The psychological effect on the travelling public of power-operated doors
of the type installed could not be overlooked; there was bound to be a certain
feeling of resentment and dismay when, owing to the arbitrary closing of
the doors, some members of a party were left behind on the platform while
others had boarded the train, especially where children were involved.
Mr. Blackshaw (Visitor) said the impression whieh would undoubtedly be gained
from the Paper was that the door gear was the acme of simplicity, but he
could give the assurance that there was far more in it than would appear
from the Author’s very brief Paper and from the very simple diagrams
that accompanied it. There had been at times what seemed insurmountable
difficulties, and it was extraordinary to find what could really happen with
such a simple thing as a piece of door-operating mechanism. When he first
came in contact with it. he thought that there could not be much in a gear
to open a door, and that it must be a perfectly simple job: but he was very
soon disillusioned.
Mr. L. Lynes said one could not fail, when travelling on the rolling stock
of the London Passenger Transport Board, to appreciate the excellence of
the door performance, and since he had had occasion recently to live in the
London district he had come to admire it more than ever. It occurred to him
while he was on his way to the meenng that he had yet to see a door fail,
and after seeing the staggering figures given at the end of the Paper he
wondered whether he ever would; the odds seemed to be many millions to one
that he would not. He was not sure whether that excellent performance was
to be attributed to the design or to the maintenance; probably both were
entitled to the credit, but it was an outstanding testimonial that the doors
gave such an excellent performance.
The tunnels presented a situation to which the sliding door was the obvious
answer, and therefore the problem had been an easy one in that respect.
He was struck by the noiselessness of the operation compared with the hinged
doors on ordinary suburban stock, which made such a shattering noise when
they were swung to. Another feature was the rapidity of their operation.
He had been noting the time taken to detrain and take on passengers, and
very often the whole movement was carried out in something of the order of
ten seconds. That was partly due to the orderliness with which passengers
were able to alight, thanks to the conveniently-placed and wide doors.
He had been interested in the Author’s remark about soldiers opening
doors which were closed. He noticed recently a number of hefty house-repairers
come along and hold the doors back while they all got in, and he wondered
what took place so far as the guard was concerned during that operation.
It would be interesting to know how the guard was made aware that a disturbance
of the ordinary working was taking place. In another case a lady who had
travelled past her station pressed the push-buttbn. Nothing happened, but
he would like to know what took place as far as the guard was concerned when
those operations were carried out.
Discussion: g public. W.A. Agnew (104-5) stated that the first use of
air-operated doors in Britain was on the District Railway in 1905, when over
400 cars were fitted with air-operated sliding doors, and also had centre
doors. It was true that those doors had a very brief existence; the public
did not like them, and even the comic Press made fun of
them.
Hopking (107) mentioned that on the Tyneside electric
lines they had suffered not from too much friction on the doors but from
too little. They did not use air-operated doors, but in the early days the
doors ran too well, and this led to complaints. They had therefore to fit
a small brake in connection with the passengers’ handle which put pressure
on the rail except when the door was being deliberately opened or closed,
and that overcame the difficulty. He would like to ask the Author why it
had not been possible even in war-time to operate the passenger push-button.
He could understand that passengers must not be allowed to open the door
in the blackout if the train was not at a station, but he assumed that the
guard had some means of preventing that being done. On the other hand, the
incoming passenger might even in the blackout be allowed to open the door,
provided the guard closed it.
White, J. (Paper 453)
Notes on braking of railway vehicles [with special refernce to compressed
air equipment]. 110-130. Disc.: 130-8.
Joint Meeting of the Institution of Locomotive Engineers, and the
Institution of Engineers, Australia (Sydney Division) held at Science House,
Sydney, on 7 December 1943: The Chairman of the Mechanical Engineering Branch
of the Institution of Engineers, Australia, was in the Chair.
It has been well established that higher rates of acceleration and deceleration
are not only necessary for the improvement of the service, but the cost of
providing these improvements is economically warranted by the more intensive
use of rolling stock, permanent way, and facilities that result. In recent
years considerable capital expenditure has taken place in New York and London
directed to securing improved acceleration and braking.
In order that the efficiency of suburban transport systems may be maintained
at a high level, it seems important that the ultimate objectives of the service
should be determined, particularly in regard to rates of acceleration and
deceleration. Once such a determination is made, Selection of accelerating
and braking equipment should be made in accordance therewith. It would probably
not be necessary to immediately apply all of the equipment ultimately required,
but all equipment applied should be regarded as an instalment of the final
scheme. Otherwise, premature obsolescence, and expensive replacements may
be necessary in order to meet future transport requirements. DISCUSSION.
Mn Young (Member
Turner, T. Henry (Paper 452)
Prevention of corrosion and corrosion fatigue. 159-204. Disc. 204-20.
Bibliography
Sixth Ordinary General Meeting of the Session 1944-45 held at the
Institution of Mechanical Engineers, London, on Thursday, 17 May 1945, at
5.30 p.m., Mr. W. S Graff-Baker, President of the Institution, occupying
the chair.
Conclusions.
1. Corrosion and corrosion fatigue are natural phenomena to be expected by
designers in metal constructions.
2. Corrosion will turn the cleverest mechanisms into dust and scrap metals
unless they are constantly protected.
3. Corrosion prevention is better than repair.
4. Designers have not yet learnt to eliminate moisture traps and ledges where
moisture stays in contact with metal.
5. Corrosion must be fought and can be fought economically.
6. Corrosion Research must be more generously staffed and financed -preservation
is as necessary in peace as supply in war.
7. There is no discharge in the war against corrosion
The following presis appeared in
Locomotive Mag., 1945, 51,
104 et seq. In many forms of mechanical engineering where metals
and alloys are used in the form of constantly oiled moving parts corrosion
plays a rela- tively small part in the life of the component. On the other
hand railway vehicles spend their life exposed to the weather, and in such
cases where metal parts are not constantly cleaned and oiled corrosion occurs
at once if the metal is bare. Even if protective coatings are used corrosion
will still occur when in service the coating is worn through or damaged.
The rate of corrosion will then depend mainly on the moisture content and
acidity of the atmosphere in contact with the metal. Neutral and mildly alkaline
solutions are seldom corrosive, but slightly acid liquids corrode metals
rapidly. .
Axles. Fig. 1 shows the appearance of an axle which gave long service
before it failed by fatigue. Some of the old wrought iron and steel axles
have lasted 40 or 50 years, but this one would not have failed at all but
for the excessive corrosion caused by the slightly acid drip from the wet
coal of the tender of which this was the leading axle. The first axle of
tenders is apt to be corroded more than the others, because when the fireman
slakes his dusty coal water is apt to drop on the leading' axle, and the
corrosion so accentuated joins with the normal tension stresses m the axle
skin as it rotates in service, to produce dangerous grooving and accelerated
corrosion fatigue.
Other cases of the corrosion of axles have been noted near carriage lavatories,
and under fish vans, where there is sometimes appreciable drip of salty water..
Further cases investigated have been those of dining car carriage axles where
the large dynamo pulley was clamped so as to permit the retention of moisture,
with the production of a multitude of small corrosion fatigue cracks: for-
tunately they were found by the routine inspection before failure occurred.
Springs. Locomotive, carriage and wagon springs are relatively roughly
finished as com pared with the best automobile practice, and they are often
not well painted. They generally appear rusty and there can be no doubt that
corrosion plays an appreciable part in their fracture in ser vice in such
failures as occur. Their design obvi ously requires them to be subject to
repeated bend- ing. In a dry atmosphere s~ch bendmg. would be well within
their fatigue limit ; that limit for any given shape is lower where they
are in contact with moisture. The suggested improvement m finish, removal
of sharp edges, shot-blasting'to produce compression stresses in the surface
are all no doubt worth study, but coating or interleaving with zinc would
seem to be equally desirable from the cor- rosion-fatigue failure point of
view.
Tyres. The wear on main line railway tyres :is undoubtedly accelerated
by the heat crazing of the tread by cast iron brake shoes and corrosion of
the surface so roughened. Sudden failure in service seldom occurs from this
cause. On the other hand, where corrosion occurs at the back of the tyre
it is much more dangerous, for here the tyre is in tension above the point
of rail con- tact, and if water enters between the tyre and wheel centre
corrosion-fatigue is a natural conse- quence. The smoothest surface of the
tyre back and wheel centre rim, coupled with good priming, painting and
varnishing, seem sufficient in most cases, but where special difficulty is
encountered with corrosion, as in the very moist atmosphere of Malaya, experiment
might be made with the zinc coating of the wheel rim and tyre back, followed
by the most thorough painting and varnishing of the finished assembly.
Wagon underframes . Corrosion is to be seen on old steel wagon
underframes, but serious loss of section only takes place over many years
where moisture is held trapped between riveted plates, or lodges on horizontal
ledges or in corners. It is probable that the corrosion of steel railway
wagons is not the determining factor of their life in this country. They
probably become obsolescent before they are dangerously weakened by corrosion.
That would not be true if the section of the plates and members was made
appreciably thinner. It may be possible, however, to decrease the weight
of steel used in any given wagon, without mcreasmg the corrosion risk, if
use is made of the low-alloy steels to which reference is made later in the
paper. With this in mind the author suggested to the Chairman of the Corrosion
Committee and to Sir Nigel Gresley in February, 1938, the testing of four
grades of steel in the four symmetncal bot tom plates of 100 new L.N.E.R.
hopper wagons. This test has now been under observation for over five years,
and up to the present there is. no out standing difference in the rates of
corrosion measured, although two of the steels are low-alloys. These have
appreciably higher tensile strength than the mild steel or copper-bearing
normally used. The u.t.s. of the four steels under test is 29, 31, 36 and
38 tons per sq. 'in. respectively. Three-link coupling. The typical
British wagon coupling is made from wrought iron or mild steel and exposed
to atmosphenc corrosion during its whole life. There can be no doubt that
Its wear is accelerated by corrosion; and a. case can be made out for the
use of a suitable, tough low-alloy steel which would corrode at a slightly
lower rate. The same may be said of almost all chains, and the Admiralty,
which can scarcely avoid taking corrosion into account, permit lighter chains
in steel than were traditionally made from wrought iron.
Carriages. Corrosion is easily observed in carriages of main-line
railways where the sides are made from steel panels. The paint is roughened
all too quickly at the bottom edge of the windows, and the convenience of
acid cleaners lS sometimes over-ruled by this fact. A more insidious form
of corrosion occurs at the back of the panels of car- riages, and tests with
steel and with light-alloy panels have shown that they are liable to suffer
• excessive corrosion, in our suburban tunnel atrnospheres, unless
completely and continuously protected by paint, varnish or other such means.
An unusual case of corrosion noted in carriages was that of the hot-water
tanks of the war-time casualty evacuation trains. We have also noted corrosion
in compressed air pipes, and in the studs of locomotive brick arches, and
in many boiler components.
Copper:bearing Mild Steels. For many years it has been known that
the resistance of mild steel to atmospheric corrosion is considerably increased
by the addition of a small percentage of copper. Investigators have found
that the superiority of copper-bearing steels over ordinary steels of the
same variety is about 10 per cent. in pure air and 25 per cent. in industrial
atmospheres. In tunnel conditions, however, no advantage is gained.
Copper-bearing steels are suitable for bridgework and structural steelwork,
railway rolling stock and locomotives, shipbuilding, gasholders and fencing
wire. The smokebox, smokebox door and ashpan of certain locomotives have
been made of this type of steel, a typical analysis of which is: Carbon.
0.15% Manganese 0.66%,. Silicon 0.05% Suphur. Phosphorous 0.04%.
Copper.0.042%
High Nickel Alloys. These form a useful series of alloys which combine
toughness with high resist- ance to corrosion. Monel metal is a silvery-white
natural nickel-copper alloy. Official specifications give the following
percentage limits for its com- position: nickel 63-70; iron 2.5 max.; manganese
2.0 max. ; aluminium 0.5 max.; silicon 0.5 max.; carbon 0.3 max.; sulphur
0.02 max.; copper-: balance. For castings 3 or 4 per cent. silicon may be
added. Monel metal is available in the form of bar, rod, stampings, forgings,
tubes, wire, plate, sheet, strip and castings. As it is highly resistant
to the corrosive action of both pure and impure waters it has been used for
important loco- motive firebox staybolts. It has been found that water which
has been softened by lime/soda process sometimes attacks and corrodes the
valve faces of such copper-tin-(lead)-zinc bronze boiler fittings as injectors,
blow-off cocks and whistle valves. If such valves and the inserted seating
were made of Monel metal, corrosion, cutting and steam leakage would be reduced.
Boiler Plates, Tubes and Stays. In the case of' locomotive boilers,
remarkable reduction in locomotive boiler tube corrosion was soon noted in
sheds where pitting of tubes had been excessive before the feed water was
Jime/soda softened. The corrosion of boiler stays (see Fig. 2) and other
components depends almost entirely upon the 'nature of the feed .water used
and the attention given to feed-water treatment.
Water Treatment. The British main-line railway water-treatment chemists met
two years ago and submitted to their chief mechanical engineers a statement
of their agreed recommendations as regards locomotive boiler water treatment.
This measure of agreement as to policy was a valuable step forward, but the
writer is disappomted that, in practice, a primitive standard of feed water
has been forced during the war penod on many modern locomotives. The L.N.E.R.
water treat- ment section has had its attention drawn to cases of corrosion
which have caused premature failure or curtailed the useful life of metals
in a variety of circumstances. In this respect locomotive boilers using untreated
waters are a chief source of trouble and corrosion, especially of boiler
tubes, has be~n reported from many localities. The type of corrosion found
in one area is not necessanly the same as in another, for this depends upon
the nature of the feed waters evaporated. Acid waters, dissolved gases and
waters containing corrosive magnesium salts are the worst offenders, causmg
boiler tubes, barrel or roof stays to be corroded away.
111 iscellaneous. Blowdown valves and water- gauge safety balls may be mentioned
as excep- tions to the rule that the metal or alloy matters little in comparison
to the water. Stainless steel balls proved satisfactory in blowdown valves,
and bronze balls have given good service in gauge glasses, whereas aluminium
-bronze balls failed rapidly by de-aluminification when similarly used in
certain wartime locomotive gauge glasses. In some cases where alkaline salt
concentrations in the boiler have been high, lime/soda softened feed waters
have given rise to corrosion of copper stays and tubeplates. The attack usually
takes the form of wasting of stays, accompanied sometimes by honeycomb pitting
of the tubeplate. Satisfactory cures have been obtained by maintaining lower
boiler water concentrations in conjunction with an addition of tannin to
the feed water. Lime/soda softened waters with high residual sodium car-
bonate alkalinities have given trouble with cutting Fig. 3 of bronze valve
seatings, and have also attacked other bronze boiler fittings. Decreasing
the alkalinity of the treated boiler water usually reduces the trouble. .
On the L.N.E.R. there has been expene~ce of corrosion of lead in fusible
plugs (see FIg. 3) exposed to alkaline soft water. The L.M.S.R. practice
was to cover the top of the lead plugs with electro-deposited copper and
so hinder neatly such corrosion but this precaution has not yet been thought
necessary on the other main line railways.
Journal No. 186
Spencer, D.W. (Paper 453)
Notes on axle design and performance. 263-90. Disc.: 290-308.
First Ordinary General Meeting of the Centre held at the Midland Hotel,
Derby, on Wednesday, 3 October 1945, at 7.30 p.m.: Chair taken by Mr. J.
Rankin (Member cf Council).
The failure in service of a railway carriage axle is rare, but should it
occur the results might be disastrous and in any case give rise to prolonged
delay. The majority of service failures occur in the region of the wheel
geat a short distance inside the wheel hub and investigations into axle design
generally have for their object the elimination or reduction of the tendency
for fatigue cracks to develop at this point.
The problem, which is by no means a nev one, has engaged the attention of
investigators both in the United States of America and in this country and
a good deal of valuable data has been published. Broadly speaking, approaches
to the problem have been from two aspects: (a) Photoelastic study; ( b )
Series of physical tests. Several methods of reducing the sources of weakness
and increasing the strength of axles at the press-fitted portions have been
suggested, including the provision of annular stress relieving grooves on
the inside hub of the wheel, raised seats at the pressfitted portions, and
surface rolling of the wheel seats.
Ahat tempt has been made in this paper to summarise this and other information
available, and to record the experience of London Transport railways.
D.F.C. Johansen (290-8); T. Henry Turner (298-301) on metal fatigue; E.S.
Cox (301-2); T. Robson (302-3)
Graff-Baker, W.S. (Presidential Address)
The tools for the job. 310-22.
Opening General Meeting of the Session 1945-46 was held at the Institution
of Mechanical Engineers, London, on Wednesday, 26 September 1945, at
6 p.m., Mr. W.S. Graff-Baker, President of the Institution, occupying the
chair.
Important rubber in engineering paper: mentions resilient wheels used on
PCC tramcars and the shear deformation bolster springs used on same vehicles.
Also mentioned adaption of fluorescent lighting for railway rolling
stock.
Journal No. 187
McClean, H.G. (Paper 454)
The mechanical design of the latest class F high-speed electric locomotives
of the Swedish State Railways. 336-65. Disc. 365-77.
Third Ordinary General Meeting held at Institution of Mechanical
Engineers, London, on Thursday, 25 January 1945, at 5.30 p.m.: Mr. W.S.
Graff-Baker, President of the Institution, occupying the chair.
The Quill and Cup drive; Buchli or Brown Boveri drive and Wintherthur or
S.L.M. drive were considered. H. Holcroft spoke on behalf of O.V.S. Bulleid
(365-8) on the Southern Railway electric locomotives. E.S. Cox (369-72) spoke
about Bissel trucks and Cartazzi axleboxes. J.E. Spears (372). W.O. Skeat
argued that symetrical tank engines (2-6-2 and 4-6-4) did not ride as well
as unsymetrical types, such as 2-6-4T.
McIntyre, H.M. (Paper 455)
Diesel electric locomotive: running and maintenance on the Buenos Aires Great
Southern Railway. 396-487. Disc.: 487-528.
Paper presented before the Institution 2 June 1944, at Remedios de
Escalada.
Conclusion. Having seen how the whole of the motive power requirements of
the B.A.G.S. Rly. could be served by but four sizes of Diesel-electric power
plants, it might be of interest to examine some of the advantages which would
follow as a consequence.
The locomotive repair shops would show the most drastic alterations due to
the disappearance of the boiler shop, reduction in size of the smithy, foundries,
machine shop, brass shop, copper and erecting shops. This would involve some
structural
modifications of the existing buildings, so a new lay-out is suggested. The
main stripping, repair and assembly shops for the vehicles, bogies, wheels,
traction motors, and power plants would be laid out in parallel on progress
lines, under one roof with ample light and ventilation and no dividing walls.
Petty stores, pump room and engine test beds would also be accommodated under
the same roof. A schematic lay-out of such a project is shown (Fig. 52).
Only one quarter to one third of the oil fuel storage would be required at
the running sheds and the same proportion of the present travelling tank
wagons (or coal wagons) usqd in Departmental service. The water supply problem
in bad or waterless zones would be solved and water softening plants would
no longer be necessary. Coal piles would disappear.
The running sheds would not look so grimy as they do at present with ashpits
and piles of cinders, whilst the disposal and transport of these need no
longer occupy men and wagons.
Track maintenance would decrease in cost by the disappearance of hammer blows
from steam locomotives’ driving wheels.
In conclusion the author would like to thank the General Manager and the
Chief Mechanical Engineer of the B.A.G.S. Rly. for their permission to publish
these notes, and also thanks the local manager of Sulzer Bros. for information
supplied, and ’his colleagues of the Mechanical Department for invaluable
assistance given in preparing the foregoing notes, drawings and
photographs