Proceedings Institution of Mechanical Engineers:
1930-1939
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Pendred, Loughnan St. L.
Random reflections: Address by the President. 943-54.
"What I have been endeavouring to do is to stir up a spirit of courage
and adventure amongst our members. All around us we see new methods springing
up and the infallibility of old laws and old beliefs being challenged. Something
should come out of it all, and I hope our own young British engineers and
scientists will give rein to their thoughk, and the spur to their activities."
Quotations from Kipling and Robert Louis Stevenson!
Volume 120 (January to June 1931)
Unveiling of Replica of Tablet affixed to George
Stephenson's Cottage at Wylam-on-Tyne on 20 February 1931. 249-51.
Unveiled in the Institution's Headquarters by Richard W. Allen. The
original bronze tablet had been affixed to the exterior of Stephenson's cottage
in June 1929. The commission for the plaque had been given to Professor Maryon,
of Durham University, which Sir Archibald Ross undertook to cast in his own
foundry.
Gresley, H.N.
High-pressure locomotives. 101-35. Disc.:135-206 + 3 folding plates. 8 illus.,
14 diagrs., 2 tables, 2 plans.
In his paper on "High-Pressure Locomotives," read on Friday evening,
January 23, before the Institution of Mechanical Engineers, Mr. H. N. Gresley,
chief mechanical engineer of the L. & N.E. Ry., described some special
features of considerable interest relative to the water-tube boiler of the
high-pressure engine No. 10,000, which was completed to his designs at the
end of 1929 at the Darlington Works. To prevent the formation of scale in
the tubes of the boiler, so far as possible, arrangements were incorporated
to heat the feed water, so that its temperature when delivered into the water
chamber was over 400°F. or only about 50° less than that of the
saturated steam in the boiler. Much of the scale and mud was thus thrown
down in the forward portion of the top drum of the boiler, and after running
over 15,000 miles only a slight deposit of hard scale was found on the inner
rows of tubes in the firebox. Any economy in maintenance would become fully
apparent after the engine had been running for a few years.
It had been ascertained that the cost of a water-tube boiler, similar to
that fitted to No. 10,000, would not be appreciably greater than that of
the wide firebox pattern as fitted to L. &N.E. Ry. "Pacific" locomotives.
The most expensive details of the water-tube boilerthe solid forged steam
and water drums-were not subjected to the action of the fire, and consequently
might be expected to have a long life.
When stationed at Gateshead the locomotive worked express trains from York
to Edinburgh and back, involving a daily run of about 420 miles. Whilst other
engines of the "Pacific" type in the same link require washing out after
running 1,000 to 1,500 miles, this engine ran 5,000 miles without washing
out, and when opened up it was found that the boiler was exceptionally clean
and the tubes in good condition. The superheater elements of the boiler of
No. 10,000 are located in the forward portion of the central flue, and are
subject to radiant heat. In order to prevent the flame impinging directly
on the ends of the elements, a brick column is provided in the centre of
the main flue immediately in front of the brick arch. Notwithstanding this
precaution, and owing to the fact that there were no data available as to
the effect of radiant heat on superheater elements, the temperature to which
steam was superheated during the preliminary trials was excessive, temperatures
of 900°F. being obtained; consequently the lengths and area of the
superheater elements have been reduced, so that a temperature of approximately
700°F. can now be obtained, and this is regarded as sufficient. The
superheater elements are situated between the boiler and the regulator and
are, therefore, always subject to full boiler pressure. In order to prevent
overheating when the regulator is closed, the steam supplied for auxiliary
services is taken from the superheater and passes through a coil of ribbed
pipes laid in the feedwater chamber, thus raising further the temperature
of the boiler feed and at the same time de-superheating the steam. This
de-superheated steam is led to the reducing valve where its pressure is reduced
to 200 lb. per sq. in. Steam from this reducing valve supplies a manifold
pipe on the footplate across the front of the boiler above the firehole door.
From this manifold pipe steam at 200 lb. per 'sq. in. pressure is taken for
supplying all the auxiliary services, such as the injector, vacuum ejectors,
and steam brake, reversing gear, steam sanding, steam heating, whistle, and
turbo-generator. It has been possible to retain the standard steam fittings
for this purpose. Only the safety valves, regulators, and water gauges have
had to be made to suit the working pressure of 450 lb. per sq. In.
The heating surface figures are now as under:-
Firebox 919 ft2.
Combustion chamber 195 ft2.
Small tubes 872 ft2..
Total evaporative 1,986 ft2.
Superheater:
Number of elements 12
Diameter. inside 1.18 in.
Heating surface 140 ft2.. .
Total heating surface 2,126 ft2..
Having only two sets of valve gear, it was regarded as necessary to be able
to vary the cut-off of the high-pressure cylinder independently of that of
the low-pressure cylinder, and only by trial at varying cut-offs could the
best results be realised. Therefore the rocking link by which the high-pressure
valve is actuated, is so arranged that provision is made by means of a slot
and die-block to varv the travel of the valve, at the same time retaining"
the combination lever to keep the lead constant. The reversal of the low-pressure
valve-gear, and consequently of the whole engine, is actuated by the ordinary
form of steam reverser, and a similar equipment is provided to vary the
high-pressure cut-off. Both these equipments are attached to the shafts they
actuate, and being so remote from the footplate their delicate control was
not easy. This has been successfully effected by the use of telemotors; another
telemotor is also provided for operating cylinder cocks.
As built, the engine had two high-pressure cylinders 12 in. in diameter and
two low-pressure cylinders, each 20 in. in diameter, all cylinders having
26 in. stroke. It has been found that by reducing the diameter of the
high-pressure cylinders to 10 in. a more equal distribution of work between
the high-pressure and low-pressure cylinders results.
In his paper, Mr. Gresley described in some detail the notable high-pressure
locomotives which have been built by the American Locomotive Co. to the designs
of Mr. J. E. Muhlfeld for the Delaware & Hudson Railroad: the
Schmidt-Henschel three-cylinder compound locomotives, built by Henschel &
Sons for the German State Rys., as well as the Paris, Lyons & Mediterranean
Ry., and by the North British Locomotive Co. for the L.M. & S. Ry., the
Winterthur high-pressure tank locomotive built by the Swiss Locomotive &
Machine Co. to the designs of Mr. Buchli, and the Schwartzkopff-Loftier
three-cylinder locomotive, built by the Berlin . Machine Works to the order
of the German State Rys.
In opening the discussion on Mr. Gresley's paper, the President said they
had listened to an admirable paper from a chief mechanical engineer who had
produced an engine that might be considered with pride as an "all British"
production. As so many were desirous of discussing the paper, and the discussion
would probably have to be adjourned, he invited those who had come from a
long distance to speak first. Mr. Scarth, of Yarrow & Co. Ltd., said
that although the boiler of No. 10,000 departed somewhat from the usual Yarrow
form, an outstanding feature of the type had been retained in the small number
of riveted joints, and further, the water tubes could be readily inspected
internally, while ashes and coke could be easily removed. He thought higher
working pressures could be considered for future locomotives. Some interesting
remarks on the performances of the Schmidt-Henschel and Loftier locomotives
were made by Mr. Wempe of the Schmidt Superheating Co. of Cassel, and he
was followed by M. Hoffner of the French State Rys., and M. Rogers of the
P.L.M. Sir Henry Fowler then gave some of his experiences on the high-pressure
locomotive of the Delaware and Hudson RR As the President suggested that
a boiler-designer should give his views, he called on Sir John Thornycroft
to make a few comments. This gentleman gave Mr. Gresley great credit for
the way in which he had succeeded in depositing the hardness of the water
in the form of sludge, which could be blown out. Good water circulation was
of the utmost importance if the generating tubes were to be kept in order,
and he wondered, when the boiler was working very hard, if the proportions
of the heating surface were such as to give the circulation required. Mr.
R E. L. Maunsell in his remarks, said he hoped later on that Mr. Gresley
would give details of the cost of maintenance, running costs, etc. Referring
to the arrangements made at the front end for keeping the steam clear of
the cab windows, he mentioned the success of the "blinker" plates used on
the Southern Ry. Mr W. A. Stanier spoke of the Delaware & Hudson RR
locomotives which he had had an opportunity of seeing, and the troubles they
had had with too many tubes in the firebox. Lieut.-Col. E. Kitson-Clark confined
his remarks to questions as to the mechanical details of No. 10,000. He wished
for more particulars of the bogie arrangement under the firebox, and further
asked where the tail rods for the highpressure cylinders were. He also referred
to the ratio between the diameters of the high-pressure and the low-pressure
cylinders, and to the method adopted for varying the cut-off in the high-pressure
cylinders. At the resumed discussion on the 7th inst., when replying, Mr.
Gresley showed a very ingenious electrical device for ascertaining if any
scale is present in the water tubes, glowing lamps being extinguished whenever
the working end of the instrument, pushed down a tube, encountered scale.
The above is based directly on the brief summary which which appeared in
Loco. Rly Carr. Wagon Rev., 1931,
37, 38-9.
Locomotives described include the Delaware & Hudson two-cylinder compound
locomotive of 1924; the Schmidt-Henschel three-cylinder compound locomotive
of 1926; the Swiss Winterthur high-pressure locomotive (2-6-2T) of 1927;
and the Berlin Machine Works Schwartzkopff-Löffler three-cylinder locomotive
of 1930. He then described No. 10000, with its Yarrow boiler. Discussion:
N.H. Scarth (Yarrow) (Pp 135-6); F. Wempe (Schmidt)(136-7); G. Haffner (Chief
Engineer, French State Railways p. 137); A.C. Roger (French State Railways
p. 137-8); Sir Henry Fowler (138-9) who commented on
other high pressure locomotives, on the oil separator on the Löffler
boiler, and on the chimney and smoke deflectors fitted to No. 10000;
R.E.L. Maunsell (p. 140) commented on smoke deflection;
W.A. Stanier (pp 140-1) supposed that since
the days of the Brotan firebox, locomotive engineers had thought that they
would like to try water-tube fireboxes or water-tube boilers. It had been
left to the Author to show them that not only a watertube firebox but a complete
water-tube boiler was possible for a locomotive. He had had the opportunity
of seeing the Delaware and Hudson Railway engine with a water-tube firebox,
and he had gathered from Edmonds, the chief mechanical engineer of the railway,
that the trouble with the first engine which had been built had been due
to tubes of too small diameter in the firebox, and that he had subsequently
enlarged the diameter of the tubes with advantage. He asked if the Author
had found that the outer tubes in his boiler received any appreciable amount
of radiant heat from the fire.
There was little to criticize in the Paper under discussion unless one had
had experience with the type of boiler with which the Author was experimenting.
He hesitated, therefore, to express any opinion of the boiler other than
that it seemed to be a sound mechanical design. He would, however, like to
ask the Author whether he had considered, in proportioning his cylinders,
reducing the low-pressure cylinders to 18 inches diameter rather than the
high-pressure to 10 inches diameter. He also wished to ask whether the ordinary
means of lubrication with a pressure lubricator were satisfactory with
high-pressure steam.
E. Kitson Clark (141): commented on the ratio betwen the hp and lp cylinders
and cited E.W. Selby J. Instn Loco
Engrs Paper 257.
H.A. Stenning (p. 142-4) gave some details of
the stress effects experienced in the boiler, due to excessive temperatures.
Gysel (145) adhesion charcteristics of 4-6-4; Stenning said that regarded
from the point of view of economy, it seemed that the chief object of the
designers of the high-pressure locomotives which had been described . had
been to eliminate the expense of the ordinary type of firebox and its
maintenance. No high-pressure locomotives had been running for any length
of time. Apart from the American type, there was only the multi-pressure
boiler of the Schmidt type to judge of in service, and that only over a very
limited period. He was not satisfied that it was a long enough time to enable
one to draw conclusions, but it was known that at the end of three years
of more or less continuous service the water-tubes of the closed circuit
had been examined and found to be as good as when they had been installed.
He had pieces of the tubes which had been examined in his possession and
they showed no deterioration either inside or outside. If, however, circulation
in water-tube boilers or a water-tube circuit was at all inefficient, all
sorts of troubles would occur. He had encountered some of them in the
Schmidt-Henschel engine built at the North British Locomotive Company's works
in this country. Excessive temperature combined with excessive pressure had
set up stresses which were more serious in their effects than those due to
pressure alone. For modern high-pressure boilers new materials had to be
used and he was sure that the Author would admit that the choice of a suitable
material for the drum to keep it within permissible limits of weight had
been a problem. The use of special steel which was necessary tended to make
the construction costly, and it was more important to know whether the increased
capital cost was balanced by the reduction in the maintenance costs of the
firebox than to ascertain how many pounds of coal the engine burned per ton-mile.
Coal was a comparatively small factor and what was required to be known was
the total cost of drawing a ton load for a given distance.
He had doubts as to which of the two-cylinder high-pressure, or the
three-cylinder or four-cylinder compound engines, was the best arrangement.
In England the three-cylinder engine was used. Again, the proper degree of
superheat to use was a question which had been raised for many years. In
the early stages of superheating 100° P. of superheat was considered
ample. To-day 250° to 300° 3'. of superheat was customary, and
one might well consider whether a pressure of 450 psi was necessary, or whether
still higher pressures would be advantageous. There was probably some happy
mean between the highest and lowest both of pressure and temperature, but
what it was he would not like to say. Nevertheless, the answer governed the
problem of balancing capital cost and maintenance upon which the ultimate
economy rested. The Author had mentioned that one of the tubes in his locomotive
became overheated at one point. Could he give some indication of the degree
of heat to which it was subjected, and the exact location of the tube Z He
assumed the Author had employed a fire-door of the automatic type. That was
most important in high-pressure locomotives, because if anythmg went wrong
the whole of the contents would be blown out through the fire-hole pretty
quickly at a pressure of 450 psi. In the closed circuit of the locomotive
Fury built for the London, Midland and Scottish Railway, there were
120 gallons of water, and, as he himself was unfortunately aware, on an explosion
taking place in this closed circuit, the whole of this was blown out in about
three seconds. He asked if the Author had considered what would have happened
to the fire-bars as a result of using preheated air. If they were found to
deteriorate more quickly than in the normal firebox, he suggested that they
should be treated with aluminium.
He noticed that the blower pipe had been carried along so as to clean the
tubes near the centre of the boiler, but he did not think it was carried
down to the bottom of the firebox near the corners where it was rather important
to place it so as to clear the ashes from the bottom of the water-tubes in
the firebox itself. In most of the engines described, the steam-drum was
protected by cross water-tubes underneath the bottom surface, or at any rate
the drums had been taken out of the line of the fire. In the Author’s
engine, the steam-drum was immediately above the brick arch, and he was not
at all sure that it would not get burnt. The designers of the Schmidt-Henschel
engine adopted protective means, for their steam-drum was in exactly the
same position. The effect of the flame or gases of combustion circling round
the end of the brick arch was very severe and it seemed to him that there
was a blow-pipe action directly on the surface above it. He asked whether
the large smokebox had any appreciable effect on the exhaust, pressure in
the cylinders. He assumed that the baffles for circulating the gases were
now placed in such a position that no excessiv; temperature occurred in the
superheater. The difficulty of excessive superheat had also been mitigated
by moving the superheater further to the front of the engine.
He thought these locomotive experiments were the most interesting events
occurring on British railways. The railway companies had broken away from
their traditional conservatism and were now actually carrying out more
experiments here than in any other country of the world. Three such experiments
were in progress-the Author’s, the Schmidt-Henschel locomotive for the
London, Midland and Scottish Railway, and the pulverized-fuel locomotive
on the Southern Railway-all aiming to draw tons more cheaply within the allowable
limits of weight and gauge. He felt sure that as a result, the locomotive
would still maintain its position as the cheapest tractor the world had ever
seen.
W.W. Marriner (Yarrow, pp 145-7) mentioned the low loading g. was due to
hard water; Charles King (147-9) queried the efficiency of 18% claimed for
the Löffler boiler; P.J. Cowan (149-52) mentioned improvements
in boiler feed; that Horatio Allen suffered from leaky seams and stated that
wheel arrangement of 10000 was really 4-6-2-2; W. Gregson
(153-5) discussed problems of hard water with the Brotan firebox and
queried "how did No. 10,000 compare with the 250 lb per sq in in four-cylinder
simple engines of the G.W.R. which had always been noted for their economical
running" (Gresley did not respond!);
E.L. Diamond (154-6)remarked that one admired the Author’s locomotive,
not only as an ingenious product of the engineers’ skill, but most of
all because the designer had brought to his problem a broad sense of proportion,
so that this engine might be regarded as the culmination of a series of designs
and developments which had had as their object not the production of a
spectacular test figure, but the conferring of a real commercial gain to
the railway operating department. In that connexion, it was surprising that
no reference was made in the Paper to the Baldwin compound locomotive with
a boiler pressure of 350 psi which was so fully discussed by Mr. Lawford
Fry in his paper before the Institution in 1927. That locomotive also was
a sound, practical development, and not merely a freak experiment having
little relation to the actual facts “of locomotive operation.
The Author had said early in his Paper that designers of locomotives were
only following the lead set by the designers of large stationary plants and
marine engines. One had sometimes thought that that had been true too literally
; high pressures had become a fashion, and the locomotive engineer had felt
he must have his highpressure engine too. And so they had had the somewhat
anomalous position of tentative and risky experiments with enormously high
pressures whilst more than half their standard locomotives offered a comparable
possibility of economy by the elimination of valve leakage and a reduction
of their low-pressure limit by 5 or 10 psi, an economy which merely required
the redesign of their valve-gear according to the best modern practice.
For what were the facts? The theoretical utmost gain in efficiency which
could be obtained in a locomotive by increasing its pressure from 250 psi
to 450 psi. was about 20%, corresponding to an increase in the Rankine cycle
efficiency from 18½ to 22½%. That assumed roughly the same superheat
temperature in both cases, about which he would have more to say in a moment,
and a back pressure of 17psi. absolute. But how many locomotives exhausted
against a back pressure of 17psi. at their normal running speed ? Still a
minority he feared. It was not always realized that whilst it was possible
to obtain an indicator diagram showing a low back-pressure line from almost
any locomotive, that line would show a far less favourable state of affairs
at high speed, and an exhaust pressure at 25 psi absolute was much nearer
the figure actually appropriate in most cases. The reduction of that pressure
by 8 psioffered a gain of over 10%, or fully half that attainable by an increase
of boiler pressure by 200 psi. Only those who had had extensive footplate
experience knew how seldom a locomotive ran with the regulator fully open.
Indeed, thousands of locomotives scarcely ever had their regulators fully
opened, and he had often wondered what was the good of maintaining a boiler
at a pressure of even 200 psi when the steam in the cylinder never exceeded
150 psi. or so. Much of the locomotive’s work was done at a mere fraction
of its total power output, and that would considerably reduce the saving
in coal that could be expected from the highpressure locomotive in service.
Confirmation of the importance of those considerations would be found by
studying published results of locomotive tests. The coal consumption of standard
passenger locomotives had been reduced from over 4 lb. per d.h.p.-hr. to
3 lb. per d.h.p.-hr. simply by equipping them with modern long-travel piston-
or poppet-valves. The further reduction claimed for even the very high-pressure
locomotives was only to 2½ lb, and those claims were not yet fully
substantiated. Whilst they still had so many 4 Ib. per d.h.p.-hr. locomotives
running about, it was obvious which was the first method of reducing that
coal bill of £12,000,000. The question of the lower limit of pressure,
was, moreover, one that became increasingly acute as the upper limit was
raised. A locomotive which had a boiler pressure of 450 psi. required the
steam to be expanded to six times its original volume (making allowance for
the clearance steam) as compared with the three-anda- half times necessary
for a locomotive having a pressure of 250 psi, if the same back pressure
was to be maintained. In other words, if more careful attention was not given
to valve-gear and cylinder port design in the high-pressure locomotive, most
of the gain of efficiency accruing by adding 200 psi. at the upper end of
the scale would be lost by adding a few pounds per square inch
But this was not all. at the lower end ! The urgency of that consideration
was emphasized by the fact that some difficulty had been experienced in securing
adequate expansion of the steam in recent locomotives pressed to 250 lb.
per aq. in., and it had even happened in individual cases that an improvement
in coal consumption had been effected by reducing the steam pressure at the
regulator valve.
The Author was probably well enough aware of those considerations ; compounding
in itself was not sufficient to secure adequate expansion of the steam, and
one turned with the deepest interest to the table of dimensions on page 120
to find that the Author had given exceptional length of travel to his valves,
and to the cylinder drawing on page 132 to find that admirably short, straight,
and wide ports had been included in the design. Another factor which should
not be passed over was the influence of superheat temperature. Was it sufficient
that steam at 450 Ib. per sq. in. should be superheated to about the same
temperature as steam at 250 psi in locomotive practice, or were locomotive
engineers soon going to follow the stationary plant designers and hanker
after temperatures of 1,000° F. ? The Author said that a temperature
of approximately 700" 3'. was considered sufficient, and he hoped he would
allow no one to shake him in that belief, at any rate until he contemplated
adding a condenser to his equipment. It was of course true that with increase
of pressure increase of temperature was necessary to maintain the same dryness
fraction in the steam' at exhaust. But who was certain that the steam of
a modern superheater locomotive had any moisture in it at all at the end
of expansion in the cylinder when running at normal speed ? He had failed
to find any experimental evidence on this point, and an investigation that
he had made some time ago * suggested that at a high speed the degree of
superheat was so much increased by throttling at admission that the steam
was still above saturation point at the moment of release in the cylinder.
If that were so, it would be absolutely futile to enter the hazardous region
of high steam temperatures so long as the steam-locomotive remained, by the
necessity of its circumstances, so much more rough-and-ready an affair than
the power generating steam-plant.
R.J. Glinn (156-8) spoke about mobile power stations equipped with water
tube boilers used during WW1 (illus. page 159).
Gresley in response on page 162 noted that some
questions had been raised with regard to the construction of the back of
the engine. There had been no room to put in a bogie because it would be
seen that the ashpan was placed very low. The trailing axle was really a
Bissel truck with Cartazzi slides for centralizing. The axle in front of
it was interchangeable with that used on the Pacific engines. It was a peculiar
arrangement, and it had to be adopted because of the circumstance he had
mentioned. The result, however, was that the engine was very easy riding.
There was always the possibility with a 4-6-4 type engine of getting a
symmetrical arrangement, resulting in the setting up of a swaying movement.
A dissimilar side control at the leading end from that at the trailing end
tended to break the synchronization. Certainly the engine described had no
tendency to set up a periodic side sway. As to whether it was a 4-6-4 or
a 4-6-2-2, he should certainly describe it as a 4-6-4. He imagined that 4-6-2-2
would be the correct designation of an engine having a bogie in front, followed
by six wheels coupled, a booster on the next axle, and a pair of carrying
wheels behind.
Gresley in response on page 164 Major Gregson
had referred to the magnesium limestone content of the water in the district
through which the engine No. 10,000 would have to work, and reference had
also been made by another speaker as to the desirability of softening the
water. Probably the deposit in the inner tubes of the engine was due to magnesium
limestone; it had been very hard. On the question of watersoftening generally,
not only for the engine under discussion, but for all the existing engines,
he was firmly of opinion that if the water in England could be treated ao
as to be similar to that which was available in Scotland, the expenditure
on the water-softening plants would be repaid in a comparatively short time
by the lower cost of maintenance of locomotive fireboxes. In Scotland engines
were running their full time between general repairs with practically no
dirt in the boiler. One of the new Pacific engines of the L.N.E.R. was stationed
in the Edinburgh district, and ran between Edinburgh and Glasgow and Edinburgh
and Berwick, and also to Newcastle. After running 90,000 miles it had come
into the works for general repair. He was at the works at the time, and he
had himself examined the firebox. It looked perfect, and not a single stay
had to be renewed. If that engine had been running in England south of the
Tweed, 200 or 300 stays would probably have had to be renewed after running
that mileage. The total life of a firebox in Scotland was a great deal longer
than that of a firebox in England.
The paper was discussed in Manchester on 5 February and the following
contributed: H.L. Guy (165-7);
Captain H.P.M. Beames (166-7) said it afforded
him very great pleasure to pay tribute to his old friend, the Author, and
he was sure that every one who had watched the progress of locomotive No.
10,000 would have been impressed with the courage and resourcefulness shown
in its design. Moreover, to those who, like himself, had to maintain boilers
of the Stephenson type, the successful attempt which the Author had made
to eliminate large flat stayed surfaces promised future relief from a great
deal of trouble. Indeed, the presence of those surfaces had been one of the
reasons which had restricted the advance of pressure in locomotives hitherto.
He wondered, incidentally, what trade was supposed to deal with the building
and maintenance of a boiler of that type. He could foresee some lively
controversy between the fitter, the boiler-maker, and the tuber ! On looking
at the diagram of the locomotive, it would appear that the centre of gravity
was pitched rather high and that the engine might be unsteady, but he understood
that at high speeds it was a particularly steady-running machine. It might
also be supposed from the diagram that as a result of the free passage through
the boiler given to the flue-gases the smokebox temperature might be rather
high. He asked what this temperature was, and mentioned that in an engine
of the " Royal Scot " type a smokebox temperature of 650' F. was attained
under certain conditions. Could the Author also say how much water per pound
of fuel was evaporated ? He inquired, further, whether any trouble was
experienced in keeping up the refractory walls between the flues and the
surrounding air chamber, and whether any trouble was experienced due to
evaporation.
One of the difficulties with the ordinary type of superheater boiler was
that the superheater was confined in flue tubes which frequently became blocked
with cinders. In the type of locomotive they were now discussing, however,
that trouble could not occur, but he nevertheless supposed that a certain
amount of ash passed through the superheater, and he asked what means were
adopted to clean it. Another point which would appeal to engineers was that
the feed-water in the Author's locomotive was fed to the boiler by injectors,
and it was not necessary therefore to incorporate a complicated system of
pumps as in some of the other locomotives which had been described. In view,
however, of the very high velocity with which the feed-water had to pass
through the injectors he wondered if there might not be some trouble due
to erosion of the cones.
He had asked that question in America when he had seen the first of the
high-pressure What kind of piston packing was used? locomotives, and he had
been assured that the packing in the locomotive at that time, after about
six months’ running, was the original packing fitted in the engine.
The packing and lubrication, indeed, had been so satisfactory that no alteration
had been required.. He saw that a special form of regulator was used in the
Author’s engine. Was it a multiple-valve regulator, and did it give
any trouble due to the high pressure of the steam ? Finally, he asked how
the engine-drivers and the fwemen reacted to the higher pressure, for he
well remembered the time when an old driver had handed in his resignation
because the boiler pressure of his locomotive was increased from 6 to 12
Ib. per sq. in.
J.N. Gresham (167); R.C. Bond (167) mentioned
he had recently riden on one of the German Schmidt-Henschel high-pressure
locomotives and of seeing the Schwartzkopff-Loffler engine, and he had been
struck by the complication of those machines. The Schmidt-Henschel locomotive,
however, did its work very satisfactorily, and appeared to require very little
additional attention on the part of the engine crew. The only added
responsibility was the maintenance of two water levels in place of one, which,
under certain conditions, might be difficult. He thought that what was so
very satisfactory about Gresley’s locomotive No. 10,000 was its essentially
British simplicity, and whilst, as the Author had said, a number of years
would have to elapse before any definite results could be obtained in regard
to actual savings, he thought there was not much doubt that the maintenance
cost of the locomotive should be very little, if any, more than in normal
circumstances. He would have liked to have seen some indicator diagrams and
to have had particulars of the performance of the engine measured in drawbar
horse-power output. The locomotive was interesting not only as a high-pressure
locomotive fitted with a water-tube boiler, but also as a high-pressure compound.
With one notable exception, the L.M.S. standard three-cylinder compound,
compound locomotives had not been a success in this country. In his opinion
the L.M.S. engines owed their outstanding success primarily to the simplicity
of their design and to the fact that there was very little possibility of
their being handled other than was intended by the designer. He felt, therefore,
that the time would come when the Author would find it desirable to combine
the control of the high and low-pressure cut-offs on one reversing lever.
Although a welltrained driver might be able to arrange the cut-offs to the
best advantage under varying working conditions, in many instances men had
their own personal ideas, which did not always lead to efficient results.
He inquired whether it had been necessary to fit non-return valves connecting
the low-pressure steam-chests with the ends of the high-pressure cylinders
in order to place them in equilibrium when starting away from rest on the
low-pressure cylinders. The reduction in diameter of the high-pressure cylinders
from 12 inches to 10 inches altered the ratio of the high- and low-pressure
cylinder volumes from 1 to 2.77 to 1 to 4, and that in itself called for
comment. The Author had stated that he had found it necessary to redistribute
the work between the high- and low-pressure cylinders, but he wondered whether
that could not have been done merely by altering the cut-off in the high-pressure
cylinders relative to that in the low-pressure cylinders. With the reduction
of high-pressure cylinder volume it appeared to him that it would be possible
either to increase or decrease the proportion of work done in the highpressure
cylinders according to the relation of the cut-offs in the two cylinders.
He would like to know, therefore, whether it was desired to increase or decrease
the work done in the high-pressure cylinders and also what were the cylinder
clearances and the receiver volume, since both would have a considerable
effect on indicator diagrams. The high-pressure cylinder had a 34-inch piston-rod
but no tail-rod. With so small a cylinder that would give a difference of
roughly 12 per cent in the forces on each side of the piston, and he thought
it might have been desirable to provide a tail-rod. In examining the design
of the boiler, a point which struck him was that the brickwork round the
grate was somewhat shallow- If the engine were working with a fairly thick
fire at the back of the firebox there might be some risk of burning coal
coming into contact with the tubes, and be thought, therefore, that it might
be desirable to carry the brickwork slightly higher, Captain Beames had referred
to the accumulation of unburned fuel. Normally it deposited in the smokebox
and was removed at the end of a run. He wondered, in the case of locomotive
No. l0,000, not only how it was removed, but exactly where it accumulated.
The Author had pointed out that in the operation of any water-tube boiler,
prevention of scale formation was of the first importance ; if scale was
kept out of the boiler it must obviously be deposited somewhere else, perhaps
in the feed-water heater, and he would be interested to know how frequently
the latter had to receive attention. He did not know whether it was generally
appreciated that the washing-out of boilers cost a very large sum. On one
of the British railways over 3,000 boilers were washed out each week, which
resulted in each locomotive being out of service for any time up to sixteen
hours. If all locomotives could be fitted with boilers which would run 5,000
miles instead of 1,500 miles between washing out, the saving would be very
considerable. The Author had mentioned an evaporation figure of 20,000 lb.
per hour on a four-hour basis. He asked if that was the maximum rate of
evaporation of which the boiler was capable when working a heavy train.
Considering the Author's standard 4-6-2 express passenger locomotives, working
at 180 lb. per sq. in. boiler pressure, which would probably he capable of
developing 1,500 indicated horsepower for long periods, and assuming a steam;
S. Jackson (170-2); D.W. Sanford (LMS p. 172); C.H. Browne (on scale p. 172);
E.F. Lang (on the relatively low boiler pressure p. 173) and Gresley responded
(pp. 173-6).
The paper was discussed in Leeds on 12 February: speakers included
F.C. Lea (177-8); E. Kitson Clark (178); W.T. Athey
(178-9) stated that he had entered Gateshead as an apprentice in
1887, commented on compounding and boiler scale; R. Alan Thwaites (179) observed
that the engine was in no sense a freak and he imagined that it was likely
to be the forerunner of many similar ones, though some of the Continental
engines described in the Paper might not survive. There was something very
British about engine No. 10,000 both from the point of view of mechanical
design and appearance. He thought that the only serious problem in operation
was likely to be the water supply. The Author had adopted ingenious steps
which largely but not entirely prevented the deposition of scale in the tubes,
but it was interesting to note his view that if high-pressure locomotives
came into general use it would probably be found economical to treat the
feed-water. With this he entirely agreed, but he would go even further and
suggest that it might be necessary to de-aerate it. In power-station practice
where high-pressure boilers were employed it was necessary to eliminate from
the feed-water both scale-forming solids in solution and oxygen. If oxygen
were present severe pitting was liable to take place in the top drums at
abont water-level. Boiler feed-water for an express locomotive was handled
in such a way as to aerate it almost to the point of saturation. If, however,
the water in the tender was kept under a partial vacuum, much of the oxygen
might be removed. A thin deposit of scale would of course greatly reduce
corrosion, but if in the future the water was so treated that no scale resulted,
then serious consideration would have to be given to this question of the
oxygen conten; A.W. Chapman (179 on scale); J.J. Sheridan (179-80); John
Blundell (180-1); G.A. Musgrave (181) noted his own involvement in the design
of the boiler between 1924 and 1930 when the locomotive entered service.
Gresley replied on pages 181-3.
The paper was discussed at a meeting in Glasgow on 18 March: speakers
included: Harold E. Yarrow (183-4); A.L. Mellanby (184-5);
David C. Urie (185) suggested that the boiler
was the main point of interest at the moment to locomotive engineers. He
took it that the Author’s object had been to design a high-pressure
locomotive boiler which should not greatly exceed in initial and maintenance
costs a modern locomotive boiler of standard type. Realizing that, he had
faced the fact that he must use raw water for boiler feed, and it was interesting
to note the measures which were being adopted to precipitate as much of the
solid matter as possible before the water entered the boiler tubes. Subsequent
experience in this direction would be watched with interest by all locomotive
engineers. He saw no future for a high-pressure locomotive unless its costs
were not in excess of normal locomotives built for similar duties, because
additional capital charges would quickly absorb the coal saving under normal
working conditions as distinct from selected trials. He did not expect that
the saving under such conditions could be much more than 10%. It had been
mentioned by the Author that roughly 1 ton of coal had been saved in 8 on
the round trip from London to Edinburgh. This was roughly 12½% and if
60,000 miles was the average annual mileage 150 tons of coal might be saved
per annum. This did not leave much room for additional capital cost. He very
much welcomed the remarks of Professor Mellanby in connexion with the high
pressures which were the fashion or had been the fashion until lately. Indeed,
he would say of some of the locomotives which had been described that they
were not before their time but after it. He thought, personally, that the
direction in which the Author was going was the one which was most likely
to be fruitful in its results. He had no doubt that if additional locomotives
of the type were built the cost of subsequent boilers would be considerably
less than that of the pioneer boiler, and he noticed that the Author mentioned
that the cost of this boiler should be very little in excess of that of the
standard locomotive boiler used in his Pacific locomotives. He fully agreed
that to increase the pressure from 450 to 900 or 1,200 lb. per sq. in. would
add very little to the gain in thermal efficiency, but might add considerably
to the maintenance costs.
Lindsay Foster (186-7) said that he was by no means clear as to the
mechanism of the heat transmission between the closed circuit in the
Schmidt-Henschel system and the steam evaporating drum. He presumed that
the closed circuit was merely a means of carrying the heat from the fire
to the high-pressure boiler in order to keep away from the hottest surface
of the locomotive the crude water that was used in service. It appeared from
the diagram that there was a good deal of space in the air-preheating passage
in the Author’s locomotive. Unless that space was necessary for reducing
the resistance to the passage of the air he thought the air would be considerably
more heated if it were restricted to a minimum so as to increase the velocity
and ensure turbulence.; Robert Fox (187); J.M. Harper (188); Leonard Hyde
(188-9);
George Ness (189) who chaired the meeting wondered
whether water-tube boilers might not prove advantageous for locomotives other
than main-line engines: experience with shunting locomotives for colliery
sidings had shown that as the boiler pressures had been increased, the life
of the fiebox was reduced. Whereas, some years ago, for colliery and
contractors’ purposes one could reckon on a life of from ten to twelve
years for a firebox, they were now not at all surprised to find it more or
less worn out in four years. This generally depended on the curves and the
gradient of the bank on which the locomotives were operated. He asked what
was the life of the average locomotive firebox for railway purposes, and
whether it had appreciably shortened in recent years. One thing quite evident
from the high-pressure boiler described in Mr. Gresley’s Paper was the
magnificent engineering skill displayed by its design and construction. It
was entirely different from the old type of boiler, and he thought especially
that they could not praise too highly those who had forged the drums, and
in such short time effected so great a reduction in their price.
T.E.H. Heywood (190) replying on behalf of Gresley
said that he was very much surprised to hear that fireboxes of shunting
locomotives in collieries were only lasting four years. The fireboxes of
similar locomotives on the L.N.E.R. would last ten or twelve years, though,
of course, he did not mean that they would not require any repairs during
that time. In the event of any abuse with regard to leaky tubes, it might
even be necessary to put in a new tube-plate or portion of a tube-plate.
Undoubtedly it was of primary importance in connexion with the firebox of
a locomotive that the stays and tubes should be kept tight. Experienced
boiler-makers had said that if leaks in the firebox were attended to without
delay and washing out was done properly, the firebox would last for the life
of the locomotive. Shunting up gradients produced uneven expansion in the
firebox and intensified stay and tube trouble, but he could not understand
any colliery company in that district, with its good water, having undue
trouble.
The adoption of the water-tube boiler for existing engines was a matter which
had still to be considered, and it could not be decided until further trials
had been made. Trials of the use of pulverized fuel for locomotives had been
carried out in this country, but he did not think that even Messrs. Yarrow
would go the length of saying that the use of pulverized fuel was an established
practice in marine work. It was much easier to use pulverized fuel for marine
or stationary work than in a locomotive. The cost of the Author’s locomotive
and its maintenance, and in fact the economic side of the whole experiment,
could not be stated yet. The engine was experimental, and one could not base
the capital cost of a highpressure locomotive on what this engine had cost.
He hoped a representative of Messrs. Yarrow would answer the questions about
the boiler. The work in regard to the rivets, drums, etc., was altogether
different from ordinary locomotive boiler practice ; and he and his colleagues
had learned a great deal from the work which had been executed by Messrs.
Yarrow.
T.S. Finlayson (192) asked what variation was
permissible in the high-pressure cut-off when the low-pressure cut-off was
set at 60%. The centre of gravity of the locomotive was behind the centre
of the coupled wheel-base which was inherent in the design, and he thought
that might cause a tendency to produce lateral movement at the front end
when running at high speed. The laminated springs on the bogie and coupled
wheels were comparatively short, hence the deflexions were small and might
produce harshness in running. One of the trailing trucks had a long laminated
spring while the other had coil springs, giving deflexions greater than those
of the coupled and bogie springs. It might be that in time the rear springs
would settle down and the weight on the coupled wheels increase.
Lomonossoff, G.V.
Problems of railway mechanics. 648-59. 2 diagrs.
Theoretical paper: from the point of view of analytical mechanics
a railway train is a system of rigid bodies connected partly by rigid and
partly by elastic bonds. As a rule, motion of this system is not uniform:
the forces of inertia of all the parts of a train need to be take into
consideration. These can be divided into two sections: those having progressive
motion only along the track and those having rotary motion as well. For the
latter, namely the wheels, the permanent way is a non-preventative obstacle.
If this obstacle and all bonds between the separate parts of a train were
rigid the solution of the problems of railway mechanics would be rather
easy.
Woolltscroft, G.W. The training of an engineer.705-12.
The London, Midland and Scottish Railway in Derby had three grades
of apprenticeship:
(1) Trade apprentices usually destined to become craftsmen.
(2) Priivileged apprentices, usually with secondary or public school training,
who have to pass an entrance examination. These apprentices generally commence
in the works at a later age than the former, and are allowed two mornings
per w-eek, with pay, to attend a part-time engineering course at the Derby
Technical College.
(3) The highest form of apprenticeship, namely pupils who had usually obtained
an engineering degree, and who have a still more varied workshop training
than the former.
Gresley, H.N.
Locomotive experimental stations. 23-39 Disc.: 40-53. illus., 6 diagrs.
Described and illustrated earlier or existing plants: The Chicago
& North Western Railway opened one in 1895, Columbus University initiated
one in 1899, the Pennsylvania Railway installed one at the St. Louis exhibition
in 1904 (this employed Alden brakes), the Swindon test plant opened in 1905,
the German State Railways opened a plant with Froude water brakes at Grunewald
in 1931 and a plant was under construction at Vitry-sur-Seine. Gresley noted
that a locomotive testing plant arranged on the lines outlined by the Author
embodies many features of an essentially novel character, and there is much
detail work still to be done before the scheme can be regarded as complete.
On the other hand, it is claimed that such a plant offers considerable
advantages:
(1) The provision of a wind tunnel in which a locomotive can be tested.
(2) The arrangement of coupling the supporting wheels by means of bevelled
gears directly to the longitudinal shafts produces conditions which approximate
more closely to normal running conditions. Under normal running conditions
a locomotive progresses along a fixed rail. Therefore a fixed locomotive
should drive something resembling x caterpillar track, and the nearest workable
mechanical arrangement to this is a set of supporting wheels rigidly coupled
together. This eliminates the possibility of slipping on one of the supporting
wheels, and the proportion of the power transmitted through the coupling
rods is approximately the same as that which is obtained under running
conditions.
(3) With the braking equipment concentrated in one place, fixed on rigid
foundations, and away from the supporting wheels, the brakes are more accessible
and can be more readily adjusted, and the use of flexible pipes, which is
necessary if the brakes are directly coupled to the supporting wheels, is
obviated.
In conclusion the Author submits that the provision of a British Locomotive
Experimental Station is more essential now than at any other time. On the
Continent and in America large sums of money are being expended upon the
scientific development of locomotives, and these countries are obtaining
orders in markets which were formerly wholly British. To meet this competition,
and to provide for this country locomotives of the highest efficiency, it
is necessary that we should have equipment second to none for the investigation
of locomotive economy.
Contributors to the discussion included G.V. Lomonossoff (40-2); Stanier
(42-3) who commented on the Churchward plant and improvements made to reproduce
actual running conditions on the plant and to power absorption;
C.H. Bulleid (University of Nottingham p. 43) noted that the effect
of the variable conditions on the road had been brought home to him very
vividly many years ago when he had tried to compare two loconiotives by plotting
curves for each showing the connexion between horse-power and speed. He had
secured a large number of diagrams from two totally different engines, but
when he had plotted the average curves he had found they were almost identical.
He then realized that he had not been studying the locomotives at all ; he
had been studying the train and the schedule to which it was being run !
He felt that a testing plant such as the Author had foreshadowed would be
as important to engineers as the Froude tank was to naval architects.
C.H. Kuhne (pp 43-5) spoke about the Froude water dynamometer used to test
road vehicles; T.R. Cave-Browne-Cave (page 45) spoke about wind tunnels;
F.C. Lea (46).
Kitson Clark, E.
Humanity under the hammer [Presidential Address]. 107-41.
History of the hammer and hammering.
Carpmael, Raymond.
The manufacture and use of steel railway sleepers, 315-77.
Included Round-hole loose-jaw type (Indian State Railways); Webb's
Pattern: Rafarel's Patent Sleeper (1887)
Dymond, A.W.J.
Some factors affecting the riding of coaching stock. 465-504. Disc.: 505-21.
25 illus & diagrs.
D. Raymond Carpmeal (505-6) spoke about the GWR use of the Hallade
recorder; R.F. McKay on latex foam seating; A.N. Moon (508-14) spoke about
the riding qualities of six-wheel bogies, tyre wear, overhang and portable
accelerometers supplied by the Cambridge Instrument Co.; S.R.M. Porter (514)
on the transverse velocity of the bogie frame relative to the bolster; A.S.
Quartermaine (GWR, 514-15) on newly laid rail. G.H. Sheffield (515-18): the
Pullman bogie was introduced to England by Sir James Allport of the MR.
Twinberrow, J.D.
The mechanism of electric locomotives. 51-106. Disc.: 106-54. 36 figs.
Nose-and-axle suspended motors. the expected improvement in the rate
of wear of track and of tyres was not realized by the substitution of locomotives
of this description for normal steam-locomotives. It was found that the wear
of flanges and of the rails on curves was reduced when the bogie trucks were
connected by a hinged joint, capable of transmitting shearing forces, the
wheel-base then being conveniently described as Bo +
Bo. The tendency of each truck to nose outwardly produces a reaction
on the hinge pin and slews the wheel treads across the rails, without heavy
pressure on the flanges. Axle-mounted armatures: the gearless motor, having
the armature mounted directly on the axle, was adopted by the New York Central
Railroad for working main-line trains over the electrified lines connected
with the Grand Central Terminus in New York. The first group of engines had
the 1.Do.1 wheel arrangement, but the single-axle pony trucks
as originally fitted were replaced by four-wheel bogie trucks, after the
occurrence of a disastrous derailment. Later and more powerful locomotives
had eight driving axles, assembled in two identical trucks, each main truck
being prolonged and supported at its outer end on a pivoted motor guiding
truck. This type of wheel-base may be defined as
Bo.Bo+Bo,Bo Auxiliary control
of the angular deviations of the guiding trucks was necessitated in order
to suppress hunting motion at high speed.
Bulleid, C.H.
The importance of metallurgy to the engineer. 767-72.
Very general paper which advocated a greater understanding by engineers
of iron, steel and other metals as materials. "The principles underlying
the heat-treatment of steel are not really difficult to understand, and a
knowledge of this subject is essential to-day... Engineers are generally
mystified by the phenomenon known as fatigue. There has recently been a revival
in the use of wrought iron in places where it had been replaced by steel.
It is said to be less subject to fatigue, to resist shock better, and to
corrode less rapidly than steel. If these claims are true, its use may well
be justified in spite of the fact that its tensile strength is less. Steel
castings are widely used, and when properly made they are very reliable...
Engineers are meeting great difficulty from the phenomenon known as creep".
Ends with corrosion and pitting.
Fell, L.F.R.
The compression-ignition engine and its applicability to British railway
traction. 3-33. Disc.: 34-61.
Advantages of the oil-electric system
Fuel cost approximately halved.
In most cases one engineman only required
no standby losses.
Fuel transportation charges greatly reduced.
large saving of water is effected.
Man-hours are saved in the running shed by the elimination of fire lighting,
boiler washing, and locomotive requirements (i.e. fire cleaning, turning,
and taking water).
Continuous 24-hour day service can be obtained when necessary, and the engine
is at all times available for immediate use. Refuelling points can be placed
as conveniently as are water cranes.
Smoke and waste steam are eliminated, together with their deteriorating effects
on buildings, rolling stock and passengers’ clothing. Dead fires, smokebox
ash and boiler scale in shed pits and on the rail side are absent, thus saving
labour in their removal.
General cleanliness of the railway is improved.
Watson, F.R.B.
The production of a vacuum in an air tank by means of a steam jet. 231-65.
Disc: 266-300.
Academic research perfgormed at Bristol University. Author mentions
vacuum ejectors for railways, but neither representatives from the railways
nor from euquipment suppliers appear to have attended the meeting. The main
results of these experiments given with reference to continuous air flow
conditions through the ejector were:
(1) Over-expansion of the steam in the nozzle took place during all the tests
described, as this gave satisfactory results over a wide pressure range,
but a high vacuum could also be produced by an under-expanded jet.
(2) The series of stationary waves in the steam jet, upon which the successful
action of the ejector appeared very Iargely to depend, extended for a certain
length outwards from the nozzle.
(3) With a steady admission steam pressure and over-expansion in the nozzle
the photographs showed that the stationary waves varied thus : (a) wavelengths
increased (and therefore the overall length of wave series) with increased
vacuum; (b) waves swelled transversely with increased vacuum, and vice versa
in both cases. These results were deduced from separate experiments using
an air Pump.
(4) A direct deduction from (3) above was that the wave series was more "
tapered " in form when discharging against a gradually rising pressure along
its length (working conditions in air ejector) than when the jet discharged
into a region of nearly uniform pressure (air pump conditions).
(5) When a sliding diffuser was moved inwards over the jet the vacuum increased
and a position was reached when the core of the jet, with its layer of entrained
air, probably just filled the throat entrance. A sudden rise of about 5 inches
to the higher range of vacua then took place, and the globular part of a
wave was always observed to be inside the throat after this sudden rise.
If the movement of the diffuser was continued, and if the diffuser had a
long parallel throat, another smaller rise would take place at the next
wave.
(6) It is evident from (5) that the correct setting of the throat entrance
relative to the nozzle outlet is a very important length, and its determination
is entirely omitted in the theory of the ejector. The maximum value of this
length was found to increase with increased steam pressure, and it was evidently
some function of the wavelength in the jet outside the nozzle. At a steam
pressure of 140 psi. by gauge for the particular nozzle used, the
maximum value of this distance was practically two wavelengths.
(7) In a diffuser with a long parallel throat (a length equal to two diameters
was used) at the higher vacua, vigorous waves extended right through the
throat into the entrance of the tail piece. This type of diffuser admitted
a longer and more powerful jet than the one with a very short throat, and
it gave a higher and more nearly constant vacuum over a wider range of diffuser
setting.
(8) Of the two forms of diffuser entrance used, namely (a) short rounded
and (b) tapered, the latter gave, on the whole, better results than the
former.
(9) The performance of a steam-operated air ejector should be based on the
calculated nozzle discharge and not on the condensed steam collected. The
percentage of the true steam weight carried off by the entrained air leaving
the condenser varied very considerably on different days, but values as high
as 25%t were obtained.
(10) Low steam pressures were found to be unsuitable. The lower limit in
these experiments to give a high vacuum with a fairly good steam-air ratio
was about 120 psi by gauge. At this steam pressure the vacuum produced was
nearly 25 inches and the steam-air ratio was 10.4, the steam quantity used
being the calculated nozzle discharge when the initial superheat was
10°F.
Schuster, L.W.
The investigation of the mechanical breakdown of prime movers and boiler
plant. 337-479.
Volume 125 (July to December 1933)
Russell, Robert
Factors affecting the grip in force, shrink, and expansion fits. 493-535.
Lomonossoff, G.V.
Diesel traction. 537-613. Bibliography (95 citations). 36 diagrs.
Read before the North Western branch in Manchester on 5 October 1933,
and before the North Eastern branch in Newcastle upon Tyne on 28 March 1934.
Intriguingly this Russian-authored paper began with a brief historical sketch
of locomotive development in England. .
Locomotives with a reciprocating non-condensing steam engine have three serious disadvantages:
The presence of harmful horizontal and vertical forces which produce recoiling and “hammer blow.” In the latter respect a considerable inclination of the cylinders is especially harmful.
Excessive fuel consumption. The overall efficiency of the Planet was less than 2%, and for the very latest steam locomotives of the reciprocating type did not exceed 11%. On the other hand, even a second-rate motor car has an efficiency of more than 20%. The two-stroke double-acting diesel engines of the German battleship Deutschland showed an efficiency of about 40%
On suburban lines electric traction has had a more definite success, nevertheless only 1.6 per cent of the worlds railway system has so far been electrified. The reasons being:
Losses between power plants and trains are very considerable. Electric locomotives do not consume more than 14% of the energy in the fuel burnt at the central power plants. On the other hand, the efficiency of the engines in omnibuses and lorries is over 20%.
Electrification approximately trebles the capital irretrievably sunk in a given transport scheme. According to the most recent data the cost of electric locomotives is only 18% of the total cost of electrification, the cost of the wiring and substations being 40%, and that of central power plants 42%
No possibility of moving electric power stations in accordance with fluctuation of traffic. Self-propelling locomotives are, however, transportable. Therefore, when there is a sudden and temporary increase in the traffic of any given district, supplementary motive power can be quickly sent to that district, and equally quickly removed again when it is no longer required.
Fuel:.Precise experiments made in Germany, Italy, and the Soviet Union,
both on "testing blocks" (test rigs) and on the track, have established that
the average efficiency of diesel locomotives is over three times as high
as that of the best reciprocating steam locomotives. On the other hand, the
same experiments show that the efficiency of any diesel locomotive depends
not only on that of the Diesel engine itself, but also on the transmission
and method of control.
In the U.S.A., 600 h.p. Diesel-electric shunting locomotives showed over
a period of two years a maintenance cost of £93 per thousand hours,
whereas this cost for corresponding steam locomotives 22 was £556. The
former figure is, however, doubtful because for certain 300 h.p. Diesel
locomotives the cost of maintenance 22 reaches £194.
Porter, S.R.M.
The mechanics of a locomotive on curved track. 457-61.
LMS Research Department.
Outlined some methods of calculating the flange forces acting at the wheels
of a locomotive or of any other rail vehicle running on curved track. For
this purpose, a locomotive is considered as an assemblage of trucks variously
linked together, a truck being defined as "any number of wheel pairs held
parallel to each other in a frame". Thus a 2-6-4 tank engine consists of
three trucks, the leading pony truck constituting the first, the coupled
wheelbase the second, and the trailing bogie the third. When a truck runs
on curved track, continuous slight slipping takes place at some or all of
the wheels, whether the latter are coupled together or not. It is possible,
however, to imagine a point, within or adjacent to the truck wheelbase, such
that if a wheel were placed there, of the same diameter and coupled to the
other wheels of the truck, it would undergo pure rolling without slip, either
longitudinally or laterally. This point is termed the centre of friction
of the truck. Cited
Uebelacker..
Concluded with three actual examples:
0-6-0 engine, weight 51 tons, passing slowly round a 40-chain curve without
superelevation ; flange force, 7.1 tons at leading coupled wheel.
2-6-4 tank engine, weight 86½ tons, travelling at 60 mile/h round a
40-chain curve superelevated 3 inches ; flange forces, 1.0 ton at pony truck
wheel, 4.3 tons at leading coupled wheel, and 4.6 tons at leading bogie wheel.
4-6-0 express engine, weight 85 tons, travelling at 70 mile/h round a 308-chain
curve superelevated 31/8 inches; flange forces, 4.6 tons at leading bogie
wheel, and 13.2 tons at leading coupled wheel. The latter figure is sufficient
to cause derailment, and in fact the conditions corresponded with a recent
accident (Weaver Junction, London Midland and Scottish Railway, 1930), where
the leading coupled wheels of an express locomotive became derailed on a
curve at high spced.
Coker, E.G. and Levi, R.
Force fits and shrinkage fits in crank webs and locomotive driving wheels.
249-275
This experimental investigation relates to a general method of measuring
stress distribution when force fits and shrinkage fits of the plane stress
type are employed in engineering practice. Important cases occur in the webs
of built-up crankshafts for locomotives and diesel engines. When the latter
are of high power and short stroke, so that crankshaft and crankpins are
large and relatively close together, the initial constructional stresses
are shown to attain high values.
More complicated cases, from an experimental point o! view, occur in the
driving wheels of locomotives with a tyre shrunk over a wheel centre having
a crank and balance weight integral therewith, while the main axle and crankpin
are forced or shrunk in. Such a case is examined with reference to a driving
wheel of the London Midland and Scottish Railway locomotive Royal Scot,
and the stress distributions measured in various parts of a model of it are
described in detail.
Haslegrave. H.L.
Relation between theory, experiment, and practice in journal bearing design.
435-75
Volume 130 (April to October 1935)
Sinclair, Harold
Recent developments in hydraulic couplings. 75-157. Disc.: 158-90.
The first hydraulic coupling to be applied to a diesel locomotive
was on a 300 h.p. locomotive, (illustrated Fig 39) constructed by Hudswell
Clarke and Company, Ltd., early in 1930 for the Junin Railway in Chile.
Discussion: T. Horbuckle (LMS, 166-7); J.F. Alcock (Hunslet, 167-9) spoke
about the locomotives supplied to the LMS;
Haworth, H.F. and A. Lysholm
Progress in design and application of the Lysholm-Smith torque converter,
with special reference to the development in England. 193-230. 9 illus.,
26 diagrs.
Hahn, Wilhelm
Voith turbo transmission. 231-47. Discussion (with two above Papers):
248-70.
T. Hornbuckle (261-2) noted the co-operation
with Haworth in the design of railcars for the LMS.
Coker, E.G. and Salvadori, M.
Stress waves in the tyres of locomotives. 493-512.
When a locomotive wheel rolls on the track, the tyre is squeezed between
the wheel centre and the rail. The former acts as a roller of variable
springiness at each point of its periphery owing to its necessarily intricate
shape, while the rail also offers a springy resistance which changes at every
point between a pair of chairs. The result of the mutual pressures exerted
by the wheel centre above and the rail below is to produce a stress wave
of variable intensity in the tyre as it advances along the rail, with a peak
value immediately over the contact area when no tractive effort is being
exerted. A photo-elastic investigation of one case of a stress wave travelling
in a tyre is described in the paper as an illustration of a number of others
of practical interest.
Volume 133 (1936)
Gresley, H.N.
[Presidential address]. 251-65. 3 tables.
An account of the development of the A4, plus a testing plant
appeal.
Thomson, A.S.T.
Investigations in film lubrication. 413-72.
...fluid friction conditions. The second short section deals with
experiments on a Deeley friction machine and shows the effect on the boundary
friction of the...
Johansen, F.C.
The air resistance of passenger trains. 91-160. Disc.: 160-208.
Engineering Research Officer, London, Midland and Scottish Railway,
Derby.
Study of air resistance, including the effects of oblique winds, performed
in a wind tunnel on reduced-scale models of LMS and LNER passenger rolling
stock. The main investigation related to trains comprising a locomotive and
six coaches, in which the aerodynamic forces on each vehicle were separately
measured ; the effect of train length on the resistance of the last coach
was determined ; and hence the resistances of trains up to twelve coaches
in length have been estimated. The forces on the bodies and chassis of certain
coaches were also separately measured.
O.V.S. Bulleid (172) "was quite unable to understand
how a theory as to what would happen with a full-size train under working
conditions could be built up from results from small models, obtained under
such different conditions. He thought Commander Cave- Browne-Cave’s
suggestion, that a relationship should be established between the results
for models and for actual trains, was an essential requirement. There was
a tendency to encourage engineers to think that streamlining would effect
savings in train working which, in practical experience, would not appear
possible. He felt, moreover, in view of the London Midland and Scottish Railway
Company’s magnificent run from Euston to Glasgow in 6 hours with an
ordinary train worked by a Pacific engine not streamlined, that the air
resistances could not be anything like as high as the figures suggested in
the paper. The subject of streamlining was, he thought, still very much in
the initial stages and required considerably more investigation."
Still, E.M.
Some factors affecting the design of heat transfer apparatus. 363-411. Disc.:
411-35.
Lawford H. Fry (414-15) regretted that though the paper gave evidence
of a great deal of work and collected a large amount of information useful
in connexion with heat transfer, the information was presented in such an
unsystematic fashion that it was very difficult to disentangle the thread
of the argument and to apply the formulae to specific cases other than those
dealt with by the author. He had spent several hours trying to apply the
processes described in the paper to the problem of computing the heat transfer
in the flue of a locomotive boiler. The results obtained were not consistent
with observed values, and he was not sure whether this was due to difficulty
in understanding and applying the methods recommended or whether the methods
could not be extended to cover the case of the flue. From an analysis of
locomotive boiler tests it was found that the following figures were typical.
A flue of 2 inches inside and 2¼ inches outside diameter, 250 inches
long, surrounded by water at 388° F., carried 288 lb. of gases of combustion
per hour. The gases entered at 2,080°F, containing 549 B.Th.U. per lb.
and came out at 614°F., containing 149 B.Th.U. per Ib. The heat given
up by the gas was 400 B.Th.U. per Ib., representing a total of 115,200 B.Th.U.
per hour for the flue. As the flue had 10.9 sq. ft. of inside hcating surface
the rate of heat transfer was 10,580 B.Th.U. per sq. ft. of surface per
hour.
Volume 135 (January to May 1937)
Kitson Clark, E.
Engineering through the nations. 533-7 + 4 plates. 8 illus.
Ancient engineering
Proceedings, General Discussion on Lubrication and Lubricants, 13th-15th
October. 119 et seq
Other reports covered intrnal combustion engines by Ricardo, turbines
(Auld and Evans) and properties and testing (Gough).
Stanier, W.A.
General discussion on lubrication. Group II. Engine lubrication (reciprocating
steam engines). 139-43.
French and German State Railways consider that various grades of
superheater cylinder oil are desirable according to the degree of superheat
obtaining in the cylinder, whereas the Canadian National and English railways
employed only one grade. Of the opinions expressed about superheater cylinder
oils, the majority favoured compounded oils, since it was considered that
at the temperature of superheated steam the oil becomes much less viscous
and the fatty oil is partly decomposed, the decomposition products helping
in the formation of stable and resistant boundary films. Of special interest
was the use of emulsified oil, prepared by the German State Railways from
superheated steam cylinder oil and lime water, for use in locomotives working
under medium loads.
German State Railways used winter and summer grades oils for journals, motion,
etc, as did some English railways, whilst Canadian National and many English
railways prefered the same grade throughout the year; one English railways
considered that the inconvenience of changing the grade of oil twice a year
outweighed any possible advantage and in its experience no advantage was
obtained when the thicker summer oil was used. It was the practice of the
English railways to use a mineral oil containing a percentage of refined
raw rape oil, the percentage depending on the different classes of work and
the experience of the companies concerned, whereas the German State and Canadian
National Railways used mineral oil only. German State Railways used a higher
viscosity oil for lubricating the journals and gear of streamline locomotives,
this also being the practice of some English railways.
German State Railways used wick trimmings to supply oil to the valve gear,
and to connecting and coupling rod bushes: English railways used worsted
trimmings for the valve gear and either worsted trimmings, needle trimmings,
or felt pads for the rods.
Fairless, Thompson
The application of the locomotive to traffic working. 333-52. 8 diagrs.
Methods for analysing of steam locomotive power during traffic working
on railways lacking special testing facilities. The determination of cylinder
and boiler output, the treatment of locomotive and train resistances, and
the application of these factors to train loading, speed, and running time.
The calculation of fuel and water consumptions on a horse-power-hour basis
is given, also the method of application to train working. Then describes
the procedure for the practical application of locomotive power to trafiic
working, and the measurement of train capacity in terms of ton-kilometres
per train hour. The engine evaluated was one of a batch of 2-8-0 goods engines
on the Central Uruguay Railway.
Parsonage, W.R.
Short biography of George Stephenson. 373-91.
Selected for publication in connexion with the centenary in 1938 of
Holy Trinity Church, Chesterfield, in which George Stephenson is buried,
and the proposed building of a George Stephenson Chancel in the church.
Pp. 386-91 are extracted from the J. Scott
Russell presentation made in 1848. Records the meeting of Stephenson
with the great American writer, Emerson, in Chesterfield early in 1848 at
Whittington House, the home of Frederick Swanwick. Emerson remarked later
that “it was worth while crossing the Atlantic were it only to have
seen Stephenson-he had such force of character and vigour of intellect.”
“He seems to have the life of many men in him.” But he was a stricken
man and the end came only a few months later. Includes photographs of
Stephenson's tomb and memorial tablet, his birthplace and a portrait of
him.
Ambady, G.K.
Diesel traction on railways. 135-43. Disc.: 143-64.
An analysis of various locomotive operating costs and the degree to
which each is influenced by the type of tractive unit selected, namely, steam
or diesel. The effect of possible higher availability or serviceability factors
with diesel locomotives was not likely to be as high as may be supposed.
Specification and design details of the various components of a diesel tractive
unit are discussed and in the particular case of a locomotive designed to
haul a load of 600 trailing tons at a maximum speed of 60 mile/h., the main
design data and performance curves are worked out with and without supercharging.
The general conclusion was that diesel operating costs compared with steam
became increasingly favourable as the power output required from the tractive
unit decreases, when the advantage of a self-propelled vehicle, such as three
unit railcar, over a train hauled by a locomotive became more pronounced.
The adoption of large diesel locomotives was likely to be restricted to fast
heavy goods traffic, and long-distance through passenger services. In India
opportunities for their application would be particularly limited. The climatic
and operating conditions will tend to accentuate the disadvantage of great
weight and high first cost, and the reduction in fuel and lubricating oil
expenditure as compared with steam traction is not likely to be such as to
compensate for this fully, at the then prices of coal and fuel oil.
Discussion: L.F.R. Fell (151-4) cited his own paper presented
in 1933 noting that As indicated by the author's general conclusion,
the operating costs of Diesel locomotives, as compared with steam, became
favourable only when the weight of the unit to be propelled was comparatively
low. G.V. Lomonossoff (156-9) claimed that in the USSR steam locomotive mileages
had reached 9000 miles per month and that this had increased the competition
against employing diesel traction.
Mowat, Magnus
British engineering societies and their aims. 333-44.
The activities and objects of the Institution of Civil Engineers and
the Institution of Mechanical Engineers are described, with notes on other
national and local associations in Great Britain. Forms an excellent survey
of the general history and state of British institutions and learned societies
in the late 1930s. Paper presented at the Semicentennial Meeting of the
Engineering Institute of Canada, in Montreal, June 1937 ; reprinted by
arrangement with the Institute.
Volume 139
de Soyres, Bernard . The birth and growth of engineering in the West
Country. 539-45.
Includes Richard Trevithick and engines and pumps built in Cornwall
by Fox, Williams and Company, of Perran Foundry, and by Harvey and Company,
of Hayle Foundry. Brunel is mentioned, but mainly for his marine
activities.
Volume 142 (July-December 1939)
Stanier, W.A.
Lightweight passenger rolling stock. 13-32 + 16 plates.
This paper makes no attempt to compare British and American practice
because of the wide difference in operating conditions prevailing in the
two countries. Developments which have taken place in the last seven years
on the LMS are described, showing the improvements in the conventional British
passenger coach. This originally consisted of a separate riveted steel underframe
and timber-framed body, but to reduce weight without sacrifice of strength,
welding and high-tensile steel have been employed and timber gradually
eliminated. This has resulted in an increasing identification of the underframe
and body which has produced an all-steel coach giving a weight of about 500
lb. per passenger seat. Means adopted include the body side and underframe
combined into the form of a Vierendeel truss, the design of which is briefly
described, together with the method of calculating the stresses in the different
members. On the constructional side, the layout of the shops and the special
presses and tools are dealt with. A method of unit assembly has been adopted
and both spot and arc welding are largely used. Details are given of the
erection into a complete coach, and of the overload tests made on the finished
structure. Particulars are given of the savings in weight attained, and the
paper concludes with suggestions as to the direction in which further progress
may be sought in the future.
Introduction. In this paper no attempt is made to compare British with American
practice. The requirements are so different. Variations in climatic conditions
alone necessitate an entirely different practice and the restrictions imposed
by the smaller loading gauge in Great Britain call for an entirely different
treatment.
In Great Britain, largely owing to high platforms at the stations, the maximum
width over the cylinders of a locomotive is 9 feet and the maximum height
13 ft. 6 in., but generally only 13 ft. 1 in. The maximum weight on an axle
is 22 tons 10 cwt. (50,000 lb.), and this limits the tractive effort of a
six-coupled engine to about 40,000 lb. The maximum weight of a train is therefore
not more than 600 tons,-/- so that to enable a reasonable number of people
to be carried with the comfort necessary for comparatively short runs, it
has been the practice to build coaches 60 feet in length and weighing 30
tons.
In the past this was achieved by having a steel underframe and a body frame
of wood with wooden panelling and roof, but for many years now the general
practice has been to have a heavy steel underframe on which is mounted a
wooden-frame coach body sheathed in steel and with a steel roof. An attempt
will be made to show the trend of British design and the various stages through
which it has passed in the effort still to build 60-foot coaches not heavier
than 30 tons each.
Ripley, C.T.
High-speed lightweight trains. 97-111.
Author was Chairman ASME Railroad Division. The purpose of this paper
is to outline the changes which have occurred during the last five years
in high-speed passenger train cars and in motive power for hauling them and
the economic factors which have brought about these changes. The new designs
for passenger cars and the materials used in their construction are discussed.
A detailed comparison of steam locomotive and Diesel-electric locomotive
characteristics as they affect the operation of these new high-speed trains
is presented, Test data are included to indicate the importance of comparative
stress in track produced by the two types of power. Reference is made to
the steady improvement which has been made in steam locomotive design, but
it is shown that there is a need for some rather extensive experimentation
to make this type of power more suitable for this particular class of service.
In conclusion, the author presents his views on the general results which
have been secured from the operation of these new trains and the probable
trend in their future development.
Newberry, C.W.
An investigation into the occurrence and causes of locomotive tyre failures.
289-303 + 4 plates.
A detailed investigation was made by the LMS Research Department into
the causes of locomotive tyre faihres from two standpoints: first to determine
the cause of any particular failure, and second to find general relationships
between effect and cause in the matter of tyre defects. Examples are given
of the examination of individual failures, and of experimental work directed
to the improvement of wheel and tyre. In a statistical review, it is shown
that fatigue is the major cause of tyre failure, and many of the factors
which might influence the development of fatigue failure have been critically
examined and their responsibility assessed. In conclusion it is noted how,
by a change in tyre boring methods to increase the effective fatigue strength
of the tyre, and by modifications in design to ensure more uniform stress
distribution in the tyre, the occurrence of fatigue failures has steadily
declined.