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