Journal Institution of Locomotive Engineers
Volume 26 (1936)
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Journal No. 129
Allen, A. (Paper 347)
Rail cars in service in Northern Ireland. 2-36. Disc.: 36-44. 9 illus., 9 diagrs.
Paper presented in London on 28 November 1935//Third Ordinary General Meeting of the Session 1935-36 was held at the Institution of Mechanical Engineers, Storeys Gate, London, on Thursday, the 28 November 1935, at 6.0 p.m., Mr. A. C. Carr, President, occupying the chair. Progress from the the very basic vehicles used on the County Donegal Railway to sophisticated articulated units on the Great Northern Railway.
That the rail car services introduced in County Donegal were successful, was shown from the following extracts from a Report of the County Donegal Transport Committee, appointed by the Free State Government to investigate the transport conditions in County Donegal, who in their Report dated October, 1934, state:-
. . . and altogether they seemed to us to be a bold effort to solve the railway transport difficulties in areas where the traffic is thin. That these vehicles are appreciated was evident not only from the numbers of passengers carried, but also from the desire expressed that similar vehicles should be provided on . . .
In so far, therefore, as the County Donegal Railway Joint Committee is concerned, we have no recommendations to make, being assured by representatives of the parent companies (the Great Northern Railway Company (Ireland), and the London, Midland and Scottish Railway Company), that there is no present intention to curtail the facilities now available to the public, or to cease operating any portion of the system.
Author thanked George. B. Howden, Chief Engineer of the Great Northern Railway Company (Ireland), and Henry Forbes, General Manager, County Donegal Railway, both of whom have done so much to foster the development of the rail car throughout a very trying period.
T. Hornbuckle (LMS) pp. 38-40 We hear so much about rail cars that I often wonder what is a rail car. The start off this evening with A bus on rails, then we go to something a little bigger, and we finally end up with an articulated train. All these are called rail cars.
With regard to the difference in the cost of working, a comparison has been made between steam trains and rail cars, such comparisons require very careful examination as they can be most misleading. The real difference in the cost of working as between the so-called rail car and the steam train lies in the fact that a 100 or 150 h.p. oil or petrol engine is substituted for an 800 h.p. locomotive, and also that a one-man-operated train is substituted for a t\vomen- operated train.
To effect economies or to give better service it is not necessary in every case to turn to the so-called light rail cars, and the following important points should be kept in mind. We have listened this evening to the authors description of the adaptation of forms of vehicles to railways, some of which were closed down or on the point of closing down. One cannot draw conclusions from these conditions to the more highly organised and more densely worked railways, such as one finds in this Country. One of the great difficulties that we experience in the introduction of light railway cars on to the normal British railway is that there are very few branch lines which are admittedly very light in traffic that can be worked without running into some main line station or oi er some busy junction. .All these places are elaborately signalled, and the unreliability Of light rail cars in operating signalling apparatus is one of the most serious disadvantages in connection with that type of vehicle so much so that in many cases it prexents rail cars being considered.
The only other point I should like to make is this, that it is the adaptation of the rolling stock to the traffic requirements which is the important matter. The way in which it is carried out will depend on the circumstances of each case. Also, when we talk about rail cars, let us be quite clear what it is that we really have in mind.
Awards for Papers, Session 1934-35. 45-6.
At the Fourth Ordinary General Meeting (Session 1935-36) held in the Hall of the Institution of Mechanical Engineers, Storeys Gate, Westminster, on Thursday, the 2 January, 1936, at 6.0 p.m., the chair was taken by Mr. W.A. Stanier, Vice-President.
The results of the awards made by the Council for Papers read before the members during the Session were:
Frederick Harvey Trevithick Prize awarded to Mr. J. R. Sedgfield for Paper, entitled Machine Tooling Methods and Machine Shop Reorganisation, read before the members of the South American Centre in Buenos Aires on 23 March and 14December, 1934. The prize would have been sent to Buenos Aires and presented by the Chairman of the local branch.
The Institutions Gold Medal awarded to Dr. R.P. Wagner for his Paper, entitled High Speed and the Steam Locomotive read before members in Hall of the Institution of Mechanical Engineers on 28 February 28th 1935. Stanier said: "We all know Dr. Wagner. He is regarded as one of the leading locomotive designers in the world. His name is familiar both in England and in America, and also on the Continent. I am sure it is a very great pleasure to the members that he has been awarded this Gold Medal." (The Chairman then handed the Gold Medal to Dr. Wagner amid the hearty applause of the members present.)
The Alfred Rosslin Bennett Prize awarded to Mr. T.H. Sanders for his Paper, entitled The Evolution of Railway Suspension, (Paper No. 334) read before the members in Hall of the Institution of Mechanical Engineers on 29 November 1934.
Harbord, V. (Paper No. 348)
Metals and alloys in locomotive construction. 46-62. Disc.: 62-77.
Fourth Ordinary General Meeting (Session 1935-36) of the Institution was held in the Hall of the Institution of Mechanical Engineers, Storeys Gate, Westminster, on Thursday, 2 January, 1936, at 6.0 p.m., the chair being taken by Mr. W. A. Stanier, Vice-President. The abstract was published in Locomotive Mag., 1936, 42, 22.
To meet the present day demand for greater power and higher speeds, the locomotive engineer has to meet many and varied difficulties owing to the limitations under which he has to work. It seems to be that in the reduction of weight that further advances must be sought; it is that aspect of the case that the author took for his paper. The weight of a modern locomotive of British design may be regarded as approximately 90 per cent. steel and 10 per cent. non-ferrous metals. Of the non-ferrous weight the copper firebox is the principal item, and here we meet with our first insuperable difficulty. It is one of the immutable laws of Nature that pure metals, while possessing a minimum of strength, possess the maximum conductivity, both electrical and thermal, and any attempt to increase the strength of the metal by alloying it is accompanied by a reduction in conductivity out of all proportion to the increase in strength. Of the pure metals only one possesses a better conductivity than copper, namely, silver, but even in the construction of a Silver Jubilee locomotive this must be ruled out, not only on economic grounds but also on technical grounds, for silver has a melting point no less than 223°F. lower than copper. The remaining non-ferrous metals in a locomotive form so small a proportion of the total weight that they offer little scope for any reduction. We are therefore forced to turn our attention to the ferrous alloys, and here the locomotive engineer may look for, and expect, some help from the metallurgist in view of all that has been done recently in the way of special alloy steels. A word of warning is however necessary at the outset. The special steels are the thoroughbreds of the metallurgical stable and cannot be treated with the casual disrespect which the com- mon steels have always received. It is perhaps a pity that they were ever described as alloy steels as the name has given rise to an erroneous impres- sion that their properties are due entirely to their special composition and have been brought about by the mysterious addition of small amounts of other metals such as chromium, molybdenum and vanadium. It must be pointed out that the properties of the special steels are not due entirely to their composition, but to the fact that the addition of small quantities of other elements enables them to receive special heat treatment which confers upon them their exceptional properties. The correct heat treatment for any particular steel has been determined after long experience and is an operation requiring care and skill. It follows, therefore, that any subsequent heating of the steel in the shops will not only destroy its useful properties, but is likely to result in cracking and ultimate fracture. There is another characteristic of the special steels which is sometimes apt to be overlooked. In the early days of steel it was generally accepted that the yield point was approximately half that of the breaking stress. With improved technique in steel manufacture the ratio was gradually increased to 60, and in some cases 70 per cent. In many of the special steels, however, the gap between yield and ultimate fracture is so small that engineers should take steps to ensure that the yield point of the steel is never approached as closely as when using the more common steels.
The special steels must be treated with every care and respect, and this applies not only to their treatment in the shops but must begin with the designer and the drawing office. The designer must be on the alert to see that wherever there is a change of section it shall be gradual and not abrupt, and anything in the nature of a sharp angle must be avoided like a plague. Where hitherto he has been content with, say, a 1/16 in. radius he must contrive to make it not only more, but as much more as he possibly can. At such places local skin stresses of a very high order may be reached, and a small hair crack once started will spread rapidly through the metal. Similarly, no part of the surface should be left in a rough machined condition. All operations should be finished with a very fine cut and important places should be finished by grinding.
One of the most frequent causes of fractures in service is the failure to realise sufficiently how important it is that all machined parts be well finished. Sharp angles, insufficient radii left on machined parts, and any form of sharp break on the surface, especially those subjected to alternating stresses are liable to be the starting point of failure, more especially when the highest class of material is used.
Improvements and advances are only made at the expense of new difficulties which have to be met and the materials necessary to obtain higher duty for the same weight can only be used with safety when proper care and correct treatment is given to them.
In opening the discussion following the paper Mr. Stanier stated that when they started using these alloys they thought they had got out of their difficultes but found they were not so in many unlocked for directions. Others taking part in the discussion were Messrs. J. Clayton, M. Lewis, B. R. Byrne, S. King, J. G. B. Sams, H. Chambers, T. H. Turner, and W. F. McDermid.
Stanier (Chairman) was critical of the Izod test; and noted the difficulties of tempering manganese-molybdenum steel and the failure of rivet heads on boilers through cracking. J. Clayton (63-4) reported hair cracks in alloy steels used for connecting rod straps; M. Lewis (64-5) noted problems on connecting rods on express freight locomotives; B.R. Byrne (65-8) noted caustic concentrations, and stress cracking under corrosion; S. King (68) noted fracture in the grooves of Hiduminium alloy piston valve heads on 3-cylinder 2-6-0s (K3 class) and compared the weight of connecting rods for three-cylinder 2-8-0s (103 lbs for Hiduminium alloy as against 284lbs for carbon steel. J.G.B. Sams (68-9) commented on failure to use steel fireboxes in Britain, but as used in Colonies. Also considered that more cast iron should be used as in Ford cars; H. Chambers (69) commented on the modulus of elasticity of high tensile steels for connecting and coupling rods; T.H. Turner (69-70) considered it criminal to put the equivalent of chissel marks or stamped letters on stressed surfaces; there was a risk of caustic embrittlement in nickel steel used for boilers, and the water in the Cambridge area was equivalent to Zeolite softened water. W.R. McDermid (71) commented on the temperatures reached at the cutting edge when machining alloy steels; J. Clayton (76) noted that when chrome vanadium steel coupling rods crank pins were used on the SECR white metal had to be used instead of phosphor bronze as the bearing materail and cited Paper 124 (Volume 12): Harbord expressed surprise at this observation;..
Morse, H.M.R. (Paper No. 349)
Workshop management in the North West Railway Central Works with Gantt charts. 78-104. Disc.: 104-13.
Fourth Ordinary Branch Meeting of the Northern Branch of the Indian and Eastern Centre was held in the Committee Room, N.W. Railway Headquarters Office, Lahore, on Saturday, 16 March, 1935, at 10.15, the chair being taken by D. Cardew
Journal No. 130
Major H.P.M. Beames (125-6) noted that he had known Gresley "since we served our time together" at Crewe and that Gresley had to be congratulated for prolonging the life of the steam locomotive. Gresley mainly spoke about the Guests: M. Lancrenon and Frank Pick.
Poultney, E.C. (Paper No. 349a)
A note on the railways of the Union of South Africa (referring specially to recent locomotive practice). 135-86. Disc.: 186-207.
Fifth Ordinary General Meeting of the Session 1935-36 was held at the Institution of Mechanical Engineers, Storey's Gate, Westminster, S.W., on Thursday, January 3oth, 1936, at 6.0 p.m., Lieut.-Colonel F. R. Collins, D.S.O., in the chair.
E.C. Poultney, O.B.E., at the meeting held on 30 J nuary at the Institution of Mechanical Engineers, read an interesting paper on the "Railways of the Union of South Africa," with special reference to recent locomotive practice. Lieut.-Col. F. R. Collins, D.S.O., formerly C.M.E. of the South African Railways, occupied the chair.
As a preface to his review the author gave the leading particulars of the Union railway system. At the end of March 1934 the mileage worked amounted to 13,810; the total number of locomo- tives was 2,039, representing an aggregate tractive force of 58,661,053 lb., equal to an average of 28,770 lb. each. Passenger stock totalled 3,862 vehicles, including electric motor coaches and trailers, and the number of freight cars in service amounted to 35,301. The system is one of the largest in the world under one general manager, and is the world's most extensive narrow gauge line (3 ft. 6 in.).
When it is realised that the" Union Limited Express" operating between Cape Town and Johannesburg, replete with dining cars and the usual amenities found in modern travel, over a road practically all single line for a distance of 956 miles, maintains a mean running speed of 35 miles per hour, and at the same time negotiates grades of 1 in 50, it will be appreciated that the standard of organisation and technical skill is at a high level. The newest "Pacific" type locomo- tives can and have attained a speed of 70 miles per hour, believed to be the highest ever made on a less than standard gauge railway.
Dividing his lecture into sections, the author, in making reference to development in the permanent way, said that up to about 1929 the standard rail section was 80 lb., first put down in 1903-4. Since then the increase in traffic, and the demand for more powerful and heavier locomotives, has necessitated the introduction of a new rail of 96 lb. section of steel, with a standard length of 40 ft. Steel sleepers are largely used except in districts within 20 miles of the coast. The new rails are designed for 22 tons axle loads. Modern rolling stock was next considered. In running clearances the S.A. Railways are very fortunate, so that although limited by a 3 ft. 6 in. rail gauge it is possible to provide adequate pas- senger accommodation for the coaching stock, freight cars of considerable capacity and power- fullooomotives, thanks to the liberal overhang per- mitting the use of large cylinders. The maximum width is 10 ft., and at a height of 3 ft. 4 in., 8 ft. 4 in. The allowable height is 13 ft. Bogie vheicles are standard for passenger trains,and to a large extent also for freight; further, for the latter, all steel construction is the rule, whilst for passenger equipment steel underframing in combination with wood bodies is employed. All vehicles have a central coupler, the latest be- ing automatic; the automatic vacuum brake is standard for all stock. Passenger cars have open platforms at each end, with means to pass from one car to the next, and the compartment type side corridors predominate. Carriages are steam heated and electrically lighted. Some new cars for the more important trains have closed-in end platforms, with vestibuled connections. Some of the freight cars are of exceptional size, as an in- stance of which may be cited twelve-wheeled hopper wagons having a carrying capacity of 60 tons. There are numerous eight-wheeled cars of the hopper type of 66,000 and 112,000 lb. capa- cities. Cars for handling grain in bulk carry 80,000 lb.
Remarking on train speeds, these are not high. The main trains make 30 to 35 m.p.h. an average, and the maximum about 45 or 50 m.p.h. The distances between Johannesburg and Cape Town, Durban and East London are 956, 494, and 665 miles respectively, and the journey time speeds are 33.5, 27.3 and 23.6 m.p.h., comparing with 26.8,22.1 and 19.75 m.p.h. in 1910. Considerable attention is being given to electri- fication, especially in the vicinity of J ohannes- burg and in Natal, where the first section of the line between Pietermaritzburg and Glencoe, 170 miles, was electrically operated in 1925. This was followed by the electrification of the line be- tween Cape Town and Simonstown, 22'~ miles in 1928. The overhead system is used, and trains of eight bogie cars of the multiple-unit type. Similar trains are used on the main line which has been electrified from Cape Town to Belleville, a distance of 12 miles. The voltage is 1,500 D.C. The more important sections electrified are in Natal where 305 route miles are so worked with a line voltage of 3,000 D.e. The locomotives are equipped with four 300 h.p. motors, and have a tractive effort of 21,200 lb. The maximum work- ing speed is 45 m.p.h. These locomotives weigh 66.7 tons and run on two 4-wheeled trucks having 4 ft. wheels; two and sometimes three are re- quired on a train. The electrification of the Rand lines in the vicinity of Johannesburg will involve the conversion of 74 route miles of track, and a total of 223 track miles; this will be ready about the end of 1936.
The third section of the paper was devoted to a review of the remarkable increase both in size and capacity of the locomotives since 1911, the average gain in tractive effort being practically 40 per cent. The author went back a little farther to refer to a "Pacinc" type engine built by the North British Locomotive Co. Ltd. in 1904 to the designs of Mr. P. A. Hyde, then loco- motive superintendent of the Central South African Railways. It was then stated that it "almost appeared impossible that much further "progress could be made in increased size and "power, hampered as the locomotive superintendents have been by the narrow standard gauge." To show what has actually taken place a tabulated summary of the dimensions of representative 4-6-2 engines was shown, from which it appears that the latest Class 16E of 1935 have 1,724 sq. ft. more heating surface and 27 sq. ft. more grate area, representing gains of 95 and 72 per cent. respectively, while with a tractive effort of 35,572, the new engines show an increase of 12,392 lb. or 53 per cent. The weight is more by 28 tons, or 41 per cent.
Examples of recent passenger engines selected for description included the "Pacific" Class 16C placed in traffic in 1919 and 1922, which still do a lot of work on the main lines. They have cylinders 22 in. by 26 in.; coupled wheels 5 ft. which with a working pressure of 190 lb. give them a tractive effort of 29,890 lb. The boiler has a diameter of 64~ in. and provides 1,998 sq. ft. of heating surface, including the superheater. Piston valves and Walschaert motion with steam reversing gear are fitted. The engine stands on a wheel base of 29 ft. 9·~ in. of which 10 ft. 9 in. is rigid and the main drivers are flangeless. In common with all engines on the Union system, a powerful electric headlight is provided. The next examples noticed, introduced in 1925, were built by Baldwins. They have many features common in American practice, such as bar frames with cylinders cast with half saddles for the smokebox support and a larger boiler with steel firebox, and a large grate. The boiler is 70t in. diameter inside at the front end with its centre 8 ft. 6 in. above rails. The tender is very capacious, holding 6,000 gallons of water and 12 tons of coal.
In 1928 a further lot of similar design were placed on the line. They are known as Class 16 D.A. and some had their cylinders increased to 23 in. diameter, raising the tractive effort to 33,530 lb. During 1930 the design was repeated but the cylinders were all of the enlarged size, 23 in. by 26 in., and to meet this the grate was enlarged, also the firebox-a-the grate area being 60 sq. ft. and the firebox heating surface in- creased from 164 to 172 sq. ft. Generally speak- ing all these "Pacifics" are very much alike and can safely be said to have established the type and principles of design upon which recent locomotives are constructed. The six coupled wheels have a diameter of 5 ft. and the diameters of the leading and trailing truck wheels are 2 ft. 6 in. and 2 ft. 9 in. (2 ft. 10 in. for the 16 D.A. of 1930). The coupled wheelbase is 11 ft. and the main drivers are without flanges. In each case the working pressure is 195 lb. per sq. in. Coincident with the introduction of the 1925 "Pacifics." a new class of 4-8-2 was also built by the Baldwin Works representing as great an advance for this type as was the case for the 4-6-2 engines, compared with those previously employed. These engines, Class 15 C.B., had cyl- inders 23 in. by 28 in., and with 4 ft. 9 in. wheels and steam at 200 lb. per sq. in., the tractive effort is 39,980 lb. The coupled wheel- base is 15 ft. 9 in. and the tyres for the leading wheels are without flanges. The total engine wheelbase is 35 ft. 8 in. Before discussing the most recent locomotives, mention was made of certain experimental and articulated locomotives on the S.A.R. Before the introduction of superheated steam, compounding received attention. In 1903 two tandem com- pounds were built by the American Loco. Co. for the Cape Govt. Rys. A "Pacific" three-cyl. com- pound also was built by Neilson, Reid and Co. Ltd. It had one inside H.P. cylinder and two L.P. outside. The tandem compounds were converted to two-cylinder simples and the three-cylinder has long ceased its labours. In more recent times three- and four-cylinder simple engines have been tried.
As might be expected, with such heavy grades, and in the past light tracks and a considerable amount of curvature, many designs of articulated locomotives have been used. These comprise Mallet compounds, Garratt and modified Fairlie engines of different wheel arrangements. The largest Beyer-Garratt locomotives used in South Africa are working over the heavy grades in Natal, where they handle loads of 1,000 tons on 1 in 66 grades. These engines (Class G. L. ) weigh 211 tons, 1451 tons or 69 per cent. of which is available for adhesion. The tractive effort is 78,650 lb. obtained by four cylinders, 22 in. by 26 in. and steam at a pressure of 200 lb. in conjunction with 4 ft. driving wheels. Firing is by means of a mechanical stoker. They conform to an axle loading of 18.5 tons for operation origin- ally on an 80 lb. rail.
Mr. Poultney concluded his outline of modern practice by referring to three designs by the present chief mechanical engineer, Mr. A. G. Watson. The first is a light type of 4-8-2 engine for branch line working on a 60 lb. rail. The author dealt with this design rather fully. They have bar frames, each side being continuous from the front to the rear under the footplate. The firebox is supported at the two front corners on a cross stay, and at the hind end by a vertical plate. Steam to the cylinders is taken through an internal copper pipe of special design, fitted with a number of short small diameter pipes : through which the steam is collected. The super- heater header is equipped with the Superheater Co.'s multiple throttle regulator, but is placed on the saturated steam side, instead of between the superheater and the cylinders, as is usual. Steam distribution is by means of the "R.C." poppet valve gear, each cam box having an independent drive obtained through gears mounted on returr cranks, carried by the main crank pins. Of the 50 engines built, 25 were fitted with copper anc 25 with sleel fireboxes. The main particular: are:-cylinders, 21 in. by 26 in.; coupled wheels, 4 ft. 6 in. dia.; leading bogie wheels, 281 in. diameter; trailing truck, 2 ft. 10 in. diameter coupled wheelbase, 14 ft. 5 in.; total engine wheel- base 32 ft. 3 in. ; total wheelbase 61 ft. 8 in. work- ing pressure, 200 lb. per sq. in.; boiler diameter, first ring, inside 5 ft.; heating surface tubes and flues, 1,700 sq. ft.; firebox, 130 sq. ft.; superheater, 390 sq. ft.; combined total, 2,220 sq. ft.; grate area, 36 sq. ft. Weight on drivers, 51.70 tons; total engine, 79.25 tons; tender, 67 tons; water capacity, 6,000 gallons; coal, 12 tons. Rated tractive force, 31,849 lb. For main line services Mr. Watson has designed a new "Pacific" and a "Mountain" type of very considerable proportions, and while one hesitates to assert that these represent the limit of possibilities for the 3 ft. 6 in. gauge it certainly seems that any further considerable increase in size and power will be no easy attainment, that is, of course, while maintaining a non-articulated design.
In the general principles these two locomotives are very similar; for instance, the cylinder castings are interchangeable and in many respects the boilers are alike. Six of the "Pacifics" have been built by Henschel and Sohn and were illustrated and described in our January issue. The 16 D.A. class of 1930 has formed the basis of the "Pacific" . design with a larger firebox, but the driving wheels are 6 ft. diameter as against 5 ft. or 5 ft. 2 in., the largest used previously. To obtain the required increment in tractive effort with the larger wheels, the cylinder capacity has been considerably augmented, and at the same time also the working pressure. So far as the cylinders are concerned the size adopted for the later 4-8-2 engines, Class 15 C.A., is used, viz., 24 in. by 28 in.; these with steam at 210 lb. per sq. in. gives a tractive effort at 75 per cent. of 35,572 lb. The new 4-8-2 engines follow very closely in their main characteristics the 4-6-2 design. The boilers are very similar, but, due to the different wheel arrangement, the barrel is longer, the length between tube sheets being 22 ft. 6 in. The firebox is similar, and the grate area is 62.5 sq. ft. The total combined heating sur- face amounts to the high figure of 4,075.5 sq. ft. The coupled wheel diameter has been increased to 5 ft. as against 4 ft. 9 in. for the other large " Mountain" type locomotives. An interesting point concerning the cylinders is the provision of a semi-circular liner between the smoke box and saddle to preserve interchangeable cylinder castings, on account of the distance between the cylinder centres and the boiler centre being greater than in the case of the "Pacifics." [abstract from Locomotive Mag., 1936, 42, 50-2
Noted experiments with 4-cylinder (like the Claughton class) and 3-cylinder designs inn South Africa. Discussion: W. Cyril Williams (193-4) spoke about South African experience with Beyer Garratts. E.S. Cox also observed on the progressive use of Beyer Garratts in South African and commented on the introduction of the 4-6-4T type which had pre-dated its adoption in Britain.
Glascodine, R.T. (Paper No. 350)
Impact of railway vehicles in relation to buffer resistance. 209-38. Disc.: 238-49.
Sixth Ordinary General Meeting of the Session 1935-36 was held at the Institution of Mechanical Engineers, Storeys Gate, London, on Thursday, 27 February 1936, at 6 p.m., Mr. O. V. Bulleid, Vice-President of the Institution, occupying the chair. The following abstract appeared in Locomotive Mag., 1936, 42, 69. The increase of the general scope of buffing arrangements of the present day and the apparent discrepancy between buffers in general use and the duty to be performed formed the basis of ILocoE Paper 350 read by R.T. Glascodine at the general meeting on 27 February, when O. Bulleid took the chair. The author compared the British wagon of forty years ago, with a capacity of 8 to 10 tons, with that of 1936 which has a capacity of 12 tons; a large number of 20-ton wagons were in use, also a few bogie wagons having a capacity of 30 to 40 tons. The speed of shunting with the earlier vehicles which then met requirements was slower than it is now, and the buffer in general use was fitted with a laminated steel spring, placed in position with 3 tons initial load, after which a 7-inch stroke raised the resisting pressure to 7 tons. This gave a mean pressure of 5 tons or 2½ tons per buffer, so that the total capacity of the two buffers was 35 inch-tons. To- day the weights alone have greatly increased the conditions of buffing, but in addition the velocity at which shunting takes place,owing to the general speed-up of railway working, and especially where rail-brakes are used, has increased very greatly the blow that occurs on impact. The capacity of buffers has been increased, the working stroke being 4½ in., whilst the mean pressure may be as high as 5 tons with some steel springs, giving a total capacity of, say, 45 inch-tons on the head- stock. This increase is, however, negligible in comparison with the in- creased duty. In considering the methods of measuring the force of impact the author gave a detailed account of a test plant in the U.S.A. on which wagons are run and the action at impact recorded. By the side of the track, on the level, a long paper-covered drum is arranged to rotate at a known speed, while pencils, actuated by tappets on the car bogies, record the actual movement of the cars. The result is that each car marks on the drum its own actual movement, which, recorded against the time element of the constant movement of the paper gives the varying speed of each car. Some very accurate records have been obtained by this apparatus.
Inasmuch as no body can take up impact without yielding, the author emphasized the neces- sity of ascertaining the best means of moderating the effect of the blow. Apart from yielding it is also desirable there should be some means of moderating the effect of the intense force producing rapid acceleration. Dealing with this problem he mentioned four methods: (1) Steel springs, (2) Friction buffers, (3) Hydraulic or oil dash pots, and (4) Rubber.
With steel springs after the final pressure is reached, there is metal-to-metal contact between the buffer head and casing, which causes rapid acceleration with the heavy stresses it is desired to avoid. Friction buffers of many types have been used in the U.S.A. to improve on the behaviour of steel Springs. Friction draught gear used on passenger stock is often productive of severe and uncomfortable shocks to the passengers when starting and stopping. It is generally ad- mitted that the gear is not satisfactory, and much trouble is being taken to improve the situation. Hydraulic or oil dashpot systems are used as station end stops where it is possible to arrange buffers with a stroke, not of four or five mches, but of many feet in length.
Rubber buffers of modern type are not subject to the same objections as steel springs. In the so-called "collision buffer" in general use on British coaching stock, the final blow does not come home solid metal-to-metal, but is taken by rubber springs which are specially arranged to cushion the blows above such pressures as usually dnve the ordinary running prings home. After many passenger train collisions that have occurred during recent years the Government mspecto.rs m their reports have made remarks on the efficiency of this type of buffer in minimising damage to the vehicles and in preventing telescoping.
In view of these records as to the effectiveness of this type of buffer in preventing damage to the vehicles, the reason for this was next carefully considered. They have not an abnormally high capacity-35 to 40 inch-tons up to 50 tons pressure is all that can be reasonably claimed. The chief advantage m the use of rubber lies in the moderation of the intensity of the stress producing acceleration and in the effect of the blow. It is suggested that the efficiency of rubber is due to its non-rigid, non-metallic, semi-fluid nature. When rubber springs are oom- pressed they expand radially, so that there is a dispersal of lateral effort, or cross-component, which in a rigid train of metal work would produce vibration. It has been noticed that rubber- fitted wagons are much quieter than others during shunting operations. This can only be by elimination of vibration which in the long run spells economy. The slow recoil and low restitution make rubber preferable to steel for duties of ab- sorbing shock, such as for buffing and draw gear. The life of the rubber springs also came under discussion. Locomotive draw springs are expected to give a life of about ten years. Locomotive auxiliary bearing springs should last fifteen to twenty years, and carriage auxiliary bearing springs should give a similar life.
The life of a rubber spring, in service, depends on the amount of work it has to do. When properly applied, it has been noted that both in Britain and abroad, the general life was 15 to 17 years.
Promotion of impact resisting buffers: notes observations made in accident reports on Dinwoodie Collision, London Midland and Scottish Railway, 25 October 1928; Ashchurch, London Midland and Scottish Railway in 1929; Culgaith. London Midland and Scottish Railway, 6 March 1930; Euston. London Midland and Scottish Railway, 1 September 1931; WIinwick Junction, London Midland and Scottish Railway, 28 September 1934 and Welwyn Garden City, London and North Eastern Railway, 15 June 1935 where the buckeye coupler, with its rubber buffering, was instrumental in preventing a heavier casualty list in the rear coaches of the train.
Discussion: J.S. Tritton (238-9); J.G.B. Sams (239); C.H.S. Saunders (239); L. Lynes (239-40); T. Henry Turner (240) advocated the use of rubber in shear and suggested its application to railway buffing. This is an interesting early observation on the optimal form for rubber deformation, and is further evidence that Turner was a very rounded scientist..
Forsyth, I.C. (Paper No. 351)
Dealing with heavy excursion traffic from the motive power point of view. (abridged). 250-71. Disc.: 271-5.
Fifth Ordinary General' Meeting of the Manchestcr Centre was held in the Building of the Literary and Philosophical Society, 36, George Street, Manchester, on Tuesday, 19 March 1935, at 7 p.m., the chair being taken by Mr. R.C. Bond.
At Blackpool North including the very heavy Illuminations traffic. The paper included very detailed data, including that relating to the stabling of empty stock on Saturday 29 September 1934. Discussion: J. Hamer (271-2) who had been in-charge twenty five years before; H. Fowler( 273) who made observations about arrangements made at Cricklewood mpd to handle traffic for Empire Exhibition and Cup Final at Wembley; W. Bradley (273) noted that bearings still ran hot and demand for replacement locomotives for return workings.
Journal No. 131
Poole, A.J. (Paper No. 352)
Locomotive boiler proportions and design. 305-23. Disc.: 323-42.
Fourth Quarterly Meeting of the 1935 Session was held in Buenos Aires on 13th December, 1935. Mr. 0. Steven, the Chairman of the Centre, presided.
SUPPLEMENTARY REMARKS. The Author: I had hoped to have been able to establish a desirable ratio between water line and evaporation. Engineer Dr. Wagner, of the German State Railways, lays down a maximum velocity of steam through the water of one foot per second. This seems a very high figure-the worst I have come across with a notoriously priming boiler was 0.2ft. per second. I should be very glad if any member can give me information on this subject as, especially with Argentine waters, it appears to be of great importance to establish a minimum ratio.
Cited paper by Geer on superheating (Paper No. 211 in Volume 17). Discussion: T.J. Durnford (323 et seq
Morris, P. (Paper 353)
The construction of welded steel bodies for diesel rail cars. 343-57. 4 illus., 5 diagrs.
Fourth Ordinary General Meeting of the Southern Branch of the Indian and Eastern Centre held at the European and Anglo-Indian Institute, Perambur, Madras, on Thursday, the 18 July 1935, the Chair being taken by Mr. R. Lean.
Six railcars for the M. and S.M. Railway.
Thom, J.H. (Paper No. 354)
Fabrication of highly stressed mobile railway structures. 357-91. Disc.: 391-8. 21 figures
First Ordinary General Meeting of the Newcastle Centre held at the Royal Station Hotel, Newcastle, on Tuesday, 8 October 1935, at 7.15 p.m., the chair being taken by Mr. W. W. MacArthur.
Welding applied to diesel locomotives and rolling stock. Deals particularly with electric welding as applied by the metallic arc process, but does not include automatic welding. Discussion: E.W. Fell (392-3) failure of welded joints in locomotive boilers as compared with rivetted boilers. J.W. Hobson (391-2) history of welding: from Hawthorn Leslie in 1900.
Journal No. 132
Beaumont, J.W. (Paper No. 355)
Some suggestions on steam locomotive design. 417-24. Disc.: 424-37 .
Paper read before the lnstitution on 23 April 1936, in London, at the General Meeting held on 23 April, when the President, A.C. Carr in the Chair
The following is based on the abstract published in Locomotive Mag., 1936, 42, 159 et seq: If performance were the only criterion by which a locomotive is to be judged, a more or less complete satisfaction with the modern machines and with their possibilities of further improvement on similar lines might be justified, but there is another equally important consideration. The railway is a commercial undertalcing , and the engineer has not only to provide for the performance required, but also to ensure that it is carried out at the least possible cost. It is not enough to say that the modern machine shows, even in this respect, great advantage over its predecessors, it would be poor testimony to the designers if it aid not, the real question in these days of intensive competition is the reduction of running costs to the minimum. A typical modern locomotive may be taken having three driven axles, each carrying a weight approximately twenty tons, or sixty tons in all, and this being sufficient weight for effective adhesion for the loads and speeds required, is the total useful weight of the locomotive. The total weight, however, including the tender, coal, and water may be as much as 160 tons, giving an extra load of 100 tons which has to be hauled by the engine and must be added to the gross weight of the train. It is suggested that the reduction of this extra load is the problem of to-day.
The first suggestion for consideration is a more extended use of the articulated principle of construction. The Garratt locomotive has now had some thirty years of development and has reached a high pitch of perfection. It has been adopted in this and many other countries throughout the world, but it may be doubted whether its advantages have even yet met with the full recognition they deserve.
The arguments in its favour are generally well known, but two of them may be particularly referred to, as further suggestions depend upon them.
If sixty tons be taken as the useful weight of a locomotive, and that weight can conveniently be distributed over four or six axles instead of three, there will obviously be a large saving not only in first cost but in maintenance costs of way and works, the locomotive being the only vehicle on the railway at the present time that necessitates anything like a hundred-pound rail.
The other advantage is the greater latitude this method of construction gives to the design of the boiler or steam generator. Great advances have been made in recent years in apparatus, both electrical and mechanical, for the distant control of machinery, and there seems no reason why a locomotive should not be controlled entirely from a footplate or cab placed at either end, when the full profile of the generator in its casing could be the same as that of a coach or to the full limits the structural gauge will allow.
The ordinary locomotive boiler, with its fire tubes and blast pipe, is, with its modem improvements, still a highly efficient apparatus for its purpose, but seems to be getting very near to its limits as regards steam pressures, and higher pressures may well be one of the most important factors in future progress.
The most likely substitutes appear to be either the water tube boiler or the unitubular steam generator.
The water tube boiler is now commonly constructed for pressures of seven or eight hundred pounds and, particularly for marine work, has been made of very compact design, though perhaps its fullest efficiency is reached where size and shape are not of so much importance. It is capable of producing steam on a lower rate of fuel consumption than the locomotive boiler, and has a good storage capacity. It has already been successfully adapted for use on locomotives in various forms, both in this and other countries, and, especially with a little more lattitude as regards dimensions, offers a very promising field for the designer's consideration.
The steam generator of the unitubular type, although it is now a good many years since it was first used, has not as yet been built to a capacity which would be required for a full-sized locomotive, but in small units, generally for road vehicles, In its earlier days, Serpollet in France, White in America, and others, designed generators of this type which, so far as their steam-producing capacity was concerned, were very satisfactory, the many troubles experienced with them being almost entirely due to the controlling apparatus. Experimental work has gone on continuously ever since, notably by Doble, at first m America and for the last few years in this country; by the Siemens and Henschel companies in Germany, and others; with the result that generators of this type are now at work, both on road and railway, still of comparatively small power, but producing steam at very high pressures, fired either with solid or liquid fuel, and on a fuel consumption considerably lower than on any ordinary type of boiler.
Railcars fitted with this generator, built by Henschel, are running in Germany; a shunting locomotive, built by Sentinel Works, is at work on the L.M.S., and there seems no reason why the principle should not now be extended to much larger generators, used either singly or in multiple units. Their advantages would be very substantial; it is not, of course, possible to give actual figures regarding the saving of weight with large units, but judging by the smaller ones constructed they would weigh less than half that of an ordinary boiler. Pressures may be raised to any desirable limit, 1,200 lb. is being used in some cases, but as steam is only generated as required and there is no storage, there is no risk in using still higher pressures.
Up to recently these generators had only been fitted for firing with oil or other liquid fuel, but now both Siemens in Germany and Doble in England have successfully overcome the solid fuel difficulty and the coal or coke fired generator is now equally available. There is scope for much ingenuity in the adaptation of this method of steam generation to the most powerful of modern locomotives, but its success would in itself go far to solve the weight problem. Not only would the apparatus itself be considerably lighter than either the ordinary locomotive or the water tube boiler, but owing to its high productive capacity the weight of the fuel to be carried would be largely reduced, and, with the condensation equipment suggested later on, the weight also of the water. Firing with either liquid or solid fuel is mechanical and automatically controlled.
The next consideration is the engine, and the possibility of increasing its ratio of power to weight as has been so successfully done in the case of the internal combustion engine.
We are most of us familiar with the empirical formula for the calculation of the horse-power of motor cars for taxation purposes, and know that the actual horse-power of our engines is very much in excess of that on which we are rated. When that formula was first introduced, however, it was not very far out, as it was calculated on an engine speed of some 1,200 revs. per minute, quite an ordinary speed in those days. Petrol-driven engines have since been improved by their designers to such an extent that three or four times that speed is easily attained, and the power output is increased accordingly so that an engine, for example, rated under the formula at 12 to 14 h.p. will actually give at least 45 to 50 h.p. on the dynamometer. Diesel engine designers are now working on the same lines and increasing their power weight ratio in the same way. Can we not do the same with steam? A six- foot driving wheel running at 70 miles per hour is only making 328 revolutions per minute, and that is probably about the maximum economic speed of the type of engine used, but it is now possible to design light, high-pressure steam engines to run at three times that speed. This would, of course, involve the use of gearing even with the smallest practicable driving wheels, and not many years ago this might have been considered a serious obstacle, but with modern materials and methods of gear cutting it presents no difficulties. Each axle would be driven by a separate engine, which, in view of the high pressures to be used, would probably be of the compound or triple expansion type. It would be suspended at about its centre of gravity from the frame, and carrying on its crank shaft a gear wheel engaging directly with another on the axle of the driving wheels, a suitable ratio being provided between the two. An oil-tight casing would surround this gearing and extend over the crankshaft, guides, etc., right up to the cylinders, so that all moving parts were working in an oil bath.
Engines of this type have been fi.t:ted by several manufacturers during the last ten or twelve years into light locomotives, in combination with vari- ous kinds of gearing, and the results have been such as to encourage the idea of a much larger application of the principles involved. In fact three locomotives built by the Sentinel Co. and supplied to a metre gauge railway in Colombia are much on the lines indicated, having two bogies, each of three axles, and carrying a water tube boiler on a cradle between them. Each axle is driven by a separate engine of about 100 horse-power. Being of metre gauge, it was not possible to try them out in this country and one of them was given a short trial in Belgium, but under such circumstances it may be hardly surprising that a good deal of trouble and unforeseen difficulties were experienced when first they were put to work. These difficulties have, however, been gradually surmounted and the latest reports show that they are now fully capable of the performance for which they were designed. Another possibility which has been tried with a considerable measure of success is the application of the turbine engine to the steam locomotive. It is essentially an engine which can take full advantage of the higher pressures suggested and of the high velocity with which steam issues from the uni-tubular type of generator. In view of recent developmerrts, particularly on the L.M.S. Railway, further knowledge of its possibilities will no doubt be available and the turbine may eventually find as great a place in locomotive practice as it has already earned in the fields of marine and power station engineering. To get the fullest advantage from the use of these higher pressures and high-speed engines, whether reciprocating or turbine, the question of condensing must be considered. Either type can be worked successfully without it, but it will probably be generally ad- mitted that the efficiency of both can be materially increased by its use. It is a problem of considerable difficulty, both on account of space and weight, but the difficulties should not be insuperable. A paper was read some time ago in our South American Centre describing a condensing apparatus fi.tted to a locomotive of an ordinary type which was claimed to be entirely successful, and it was evident that a very considerable area of condensing tube could be distributed over the outer surfaces without taking up a great deal of extra room. With regard to extra weight, this would probably be more than balanced by the greatly diminished amount of water that would have to be carried, while the efficiency of the engines would be considerably improved. Another suggestion for the economical use of steam concerns the use of superheat. Many years ago the author made some rather crude experiments with a steam generator of the unitubular type by heating the coil at the output end to a red heat and getting steam from it at 1,000°F. With steam at that temperature the engine could of course only be run for cl. few moments at a time, and, though no instruments were available for actual measurement, the power output was quite extraordinary. No doubt the steam was converted with a more perfect gas and the engine, which was a compound one, took the advantage of better exparrsion, but even that did not appear fully to account for the increase in power. There are practical diffi-culties in the use of steam at such a temperature, but, after all, it is no higher than the temperature of the gases inside the cylinders of a petrol engine, and although the alternate in- duction strokes bring a charge of cool mixture in, they would soon be getting red hot in the absence of any external means of cooling. It may seem rather strange to suggest water-cooled cylinders for a steam engine, but somethmg of the kind would be needed for the use of such a highly- heated gas. Possibly, too, it would be advisable to use single acting cylinders to ensure proper lubrication. Passing the feed water through the jackets naturally suggests itself so that the heat would not be lost, as it is in the cooling system of the internal combustion engine. Some further experiment and investigation into this matter might have very interesting results.
Discussion: Stanier (424) responded in general
terms. J. Clayton (425-6) commented on the Doble boiler,
noting that he had enjoyed riding in a steam automobile fitted with a Doble
boiler and engine, that the Germans had exploited the Doble boiler to a far
greater extent, that British locomotive development was limited to the LMS
20 ton locomotive which shunted at Crewe, and that elsewhere 1200 psi boiler
pressures were achieved. (this probably tells us a lot about Clayton's interest
in the unconventional). On the Garratt type Clayton adopted a more traditional
approach, noting that the length of the type would cause problems on passenger
train working, especially at stations like Waterloo where trains of reduced
length would have to be employed. He also noted problems with the use of
Garratts in tandem where the power bogies would be adjacent and would cause
load problems on bridges. Lastly, considered the Velox-boiler locomotive
which Clayton considered that "we shall hear a great deal before long" due
to its ability to enhance steam production. W. Cyril Williams (426) countered
Clayton's criticism of loads from adjacent Garratts by noting that the mass
was less than from two conventional locomotives working in tandem and that
the Garratt type tended to obviate double heading. He also noted that his
firm (Beyer Peacock) had contributed to building and demonstrating a
turbine-condensing locomotive which operated between London and Manchester.
H. Chambers (431): This interesting Paper reminded me of an old article describing a locomotive called the "Gilderfluke" This was liberally described and illustrated in the technical Press at the time. The joke of this wonderful locomotive lay in the provision of every conceivable device, the application of which was expected to give fuel economy, and included might be mentioned tandem compound cyliaders with transmission gear to the driving wheel, internal type of brake block shoe, pre-heated air, feed water heating and many other gadgets.
It was interesting to note some reference to the possibility of refrigerating. A few years ago, the German State Railways built and tested a Diesel engine directly coupled to an air compressor set, the transmission consisting of a reciprocating unit in which the compressed air cxpanded in the cylinders similar to that of a steam type. Troubles immediately arose due to the frosting which took place round the working parts as a result of the loss of heat due to expanding the compressed air, and I venture to suggest this point to the Author.
With regard to Mr. Webbers remarks on water-tube boilers, I entirely agree with him and I thank him for the comments on the excellent work performed by the locomotive boiler. With regard to the application of various types of patent boilers, such as the VeloBx, which has been mentioned, it should be remembered that the conventional form of locomotive boiler, with its barrel and firebox securely attached to the loco,motive frames is in effect the backbone of the loco,motive as a structure. My memory goes back to experience in a contract office where in the case of a large locomotive of the 4-6-2 type it was acknowledged to be unsafe to lift the frames ur?less the boiler was in position. I heartily endorse the Author's remarks on the subjcct of welding. Recently it was decided to produce a locomotive of a general utility type and severe weight limitations were imposed. Had it not been possible to fabricate details by electric welding and so replace heavy steel and iron castings by such fabricated units the problem would have been almost impossihlc.
T. Jefferson (432-4): I haiie listened with interest to this Paper, which certainly opens up many avenues for further research in trying to improve locomotives. I have had considerable experience with the geared type of engine to which the Author refers, and as far as the engine unit and the gearing are concerned, there is nothing of which to be afraid, in the case o'f units up to, say, 250 h.p. The gears for 100 or 120 h.p., provided the pressure is kept low, as it has been in all cases of which I have had experience, show practically no \veal- alter four or five years of use. The principal trouble with small units of this description is not i n the actual drive or the engine itself; it is nearly always connected with the auxiliarics. Thcse auxiliaries give considerable trouble; they are little things, but they are just those little things that annoy everybody, put the traffic out, get a bad repute for the mechanical department, and so on. It is such things as control and electrical gear and in the case of steam units the boiler that give the trouble, and those things must be improved if we are to make a success of anything in the nay of light units or produce locomotives which will make better use of their weight. If instead of having to carry such large quantities of fuel and water we could adopt condensing and have a more efficient unit using less fuel, it would be a step in the right direction, particularly on roads where there are heavy grades, similar to those with which we have to contend abroad, going up to 5 per cent.
The problem of weight is a very important one. For a long time I have been asking for some unit which would give me, for passenger work, a minimum of 10 h.p. per ton of loaded weight, and so far I have not succeeded in getting it. It is absolutely essential to get that ratio, because in order to maintain anything like a reasonable speed on a 4 per cent. grade nothing less than that will do, and something even better is very desirable, with the idea of securing a speed on the up journey at least equal to the down safe speed. There is always a limitation of speed on the down grade for safe working, especially on 4, 46 and 5 per cent. grades with severe curvature, and on the Central Railway of Peru we set this safe speed at about 45 kms. per hour. The best that we can do on the up grade, however, is about 25 kms. per hour, so that there is plenty of scope there for increasing the speed without decreasing the load, so that we can go up at the same speed as that at which we come down.
The articulated principle, as applied particularly in Garratt engines, has been very successful in handling considerable loads in freight service-I have had no experience so far as passenger service is concerned-but the biggest trouble is boiler maintenance. There is a very large boiler, and a great amount of capital and work all locked up in one unit; and where there are but limited facilities for repairs that presents a problem. The only solution is, before going in for big boilers to make sure of the water. It is just as valuable to have good water for the small units, and in my opinion if we want to effect improvements we must start with the water. We had six Garratt locomotives on the Nitrate Rlys. on which we spent a great deal of money; I think they were the locomotives to which Mr. Williams referred, and they were at the time the biggest which his firm had produced. These locomotives ran 75,000 km. and then required new fireboxes. That had nothing to do with the design of the locomotive; it was due to the water. After incurring a cost of about approximately £2,000 each for new fireboxes, we decided to tackle the water problem and instal Permutit water softeners, with the result that the first lot of locomotives fitted with new fireboxes then did 200,000 km., required practically no boiler maintenance during this period and were still in excellent condition and good for at least another 200,000 kms.
That shows that the locomotive boiler, provided that it is treated properly and given good water and fair attention, takes a great deal of beating ; and the only direction in which an advance might be possible is in going to higher pressures without sacrificing safety. In that case we could probably look forward to geared engines and so on, but we must make sure of the steam generator, and I think that we could usefully employ our time in studying how to produce the same old but very efficient Stephenson locomotive boiler, to work with very much increased boiler pressures.
Falconer, P.L. (Paper 356)
Locomotive pipe and pipe fittings. 438-85. Disc.: 485-509.
First Quarterly Meeting of the South American Centre (Session 1936) was held at Perez on Friday, 17 April 1936.
The piping of a locomotive at first sight may appear to be rather a commonplace and uninteresting subject; an item that presents little scope for the inventive genius of the engineer, or interesting material for those with a bent for mathematical or scientific problems ; yet it performs quite an important function on the locomotive and its replacement and repair represents a substantial item in the construction and maintenance account.
Discussion: W.L. Topham (485-8): The sulphur gases in oil fuel certainly attack copper. On the old Midland Railway, when engines were fitted for oil fuel during the 1926 strike, all element joints were of copper and we could not keep the joints tight at all. The Author asked about Garratt steam pipes. These give us very little trouble. Shortly after the engines came out we fitted the connecting bolts of both telescopic and ball joints with strong spiral springs and this was successful in eliminating a lot of leakage, The only part of the pipe line to break with any frequency is the exhaust elbow under the smokebox and by casting this of brass we have brought this down to a minimum. Another form of failure which occurred from time to time was the blowing out of the curved admission pipes from their flanges at the steam chest, but this was due to faulty spot welding by the makers in England.
R. Bruce (489-90) There are one or two joints which the Author has not referred to and on which I would appreciate his opinion. First, we have the smokebox door joint in which there are several methods of fastening:
(a) The centre drawbolt and asbestos joint, also clamps
(b) The centre drawbolt and metal to metal joint.
The latter type gives good results except on the lower segment of the smokebox door and the smokebox ring which have a tendency to become badly pitted, due to moisture collecting in the smokebox when the engine is standing under steam with the chimney cover on. Perhaps the centre fastening and asbestos joint is the best and I should be pleased to have the Authors opinion re this, and if the initial expense is covered by longer senice and, if possible, to gi\e an indication as to the life of the smokebox ring.
Another joint which gives a certain amount of trouble, and is the bug-bear of the fuel inspectors life, is the cover over the Von Borries type of intercepting valve. This, on the railway on which I serve, is constructed of 1/16in. copper plate dished out to cover the valve, Banged and attached to the smokebox wrapper plate by bolts. Due to the constant movement at this point, combined with the heat from the smokebox, the copper plate becomes brittle and cracks, thus allowing air to enter the smokebox. Small outside sheds pay little attention to this important item, and drivers, as it does not directly affect their comfort, fail to book same for repair as would be the case of a small steam leak in the cab; therefore, engines very often run a considerable time before the type of leak is spotted by a travelling inspector, who usually finds it out due to the high consumption and the engine not steaming well. Smokebox flooring and perforations through smokebox wrapper plate require constant attention, especially on the older classes of engines, for the former a thin layer of mud, covered by a thin layer of cement, is probably the round the circumference of the door. most satisfactory, and I should like the Authors opinion on the latter.
E.W. Woodward (490) On pages 440 and 445 the Author invites remarks re maintenance and results of steam piping on articulated locomotives. I hope that there are other members present who deal directly with this subject, and that they will contribute with their views. The four (4-8-2+2-8-4) Beyer-Garratts in use on the B.A. and P.R. certainly did give considerable trouble from creep and consequeht leakage of connections of steam pipes soon after being put into service, but this was due mainly to lack of experience with this type of locomotive more than from any fault in design.
The connecting steam pipe between the two engines shortened up to 1½in., this being noticeable on the inner sleeve of the gland. What really happened was that the gland packing was not renewed often enough, allowing the pipe to slide in the gland after the regulator was shut, which is when the pipe shortens from contraction, but seizure of gland occurred when regulator was opened and deformation of the pipe curves occurred. This has been overcome by fitting a stainless steel inner sleeve and periodical revision of packing.
As the Author states, drain cocks are essential on the pipe lines of these locomotives as, when opening regulator after standing for a time, the cylinder purge cocks are not of sufficient size to release the amount of water accumulated from the condensed steam, and valves and piston rings suffer accordingly
E.J. Beckwith (493-6) the Garratt locomotives in service on the B.A. and P.R. These engines are provided with a total length of approximately 104ft. 6in. of 43in. bore high pressure piping, and 106ft. 6in. of 64in. exhaust steam piping. 35ft. 3in. of live steam piping- with five joints, and 37ft. gin. exhaust steam piping with six joints, are carried under the boiler bridge. Ball joints at each end connect these pipes to the centre plate castings, and troubles at these points were due to failure of the fixed cast iron casings of the ball joint. Replacement of these casings by strengthened. up brass castings overcame trouble at these points. It has been necessary to fit additional stays to the suspended portions to prevent creeping of the pipes, which we considered was the probable cause of straining action at ball joints and failure of these parts. All ball joints are lubricated by forced feed from a mechanical lubricator. Each of these suspended pipes is also provided with a sliding pipe expansion joint. The asbestos jointing material. corroded these pipes and prevented proper movement of the sliding portion. By fitting a piece of stainress steel pipe on to the sliding portion, this trouble was overcome .
Blackwood, G.W. (Paper 357)
The behaviour and maintenance of boiler tubes and superheater elements on the Western Australian Government Railway. 510-31. Disc.: 532-48. 6 illus., 9 diagrs.
25th Ordinary General Meeting of Western Australian Centre held at the Railway Institute, Perth, on Friday, 23.August 1935, at 8 p.m.: chair taken by Mr. J.W.R. Broadfoot. The discussion was continued at a further meeting on Friday, 4 October 1935.
(1) Elements are annealed before examination.
(2) Visual inspection for defects, followed by tapping for localised pitting.
(3) An approximate weight test for general loss of metal by internal corrosion.
(4) Hydraulic testing to 300lbs. per square inch after reconditioning. (Maximum boiler pressure 175 lbs.)
(5) Internal cleaning with compressed air.
(6) Cone joints reconditioned with portable grinder with a cupped emery wheel.
Journal No. 133
Stanier, W.A. Presidential Address
Recent developments in locomotive design. 553-94. 21 illus., 8 diagrs.
First Ordinary General Meeting held at the Institution of Mechanical Engineers, on Wednesday, 30 September 1936, at 6 p.m.
Chosen for the development of the locomotive design during recent years, because to locomotive men, during the last five years, the improvement in trade and the development of other means of transport had resulted in a general speeding up on the railways, and there had been a desire to show that the steam locomotive was not only capable of running heavy trains at a good average speed, but, given a suitable load, could make as good a showing as the new light trains with internal combustion engine power units. In addition, there has been a general desire to increase the average speed of all trains, with the need of a greater number of fast goods trains.
Specific designs considered included the Schmidt Henschel locomotive of the German State Railway, the Delaware & Hudson Railroad, Triple Expansion Engine (with 500 psi boiler); the Winterthur High Pressure Engine; the LMS Metropolitan-Vickers Lysholm Turbomotive, No. 6202; the Valve Gear (Outside) fitted to LMS Pacific No. 6203 with needle pin roller bearings; Baltimore & Ohio locomotive with water tube firebox; a Northern Pacific 4-8-4 locomotive; Northern Railway of France 2-8-2 tank locomotive; Pittsburg & West Virginian articulated locomotive; Express Beyer-Garratt locomotive (for PLM in Algeria); Hiawatha streamlined locomotive, 4-4-2 Type; Pennsylvania 4-6-2 locomotive; PLM. streamlined locomotive, 4-4-2 Type; Canadian National streamlined locomotive 4-8-4.; Canadian Pacific Railway streamlined locomotive, 4-4-4; German 4-6-4 streamlined locomotive; Japanese streamlined locomotive, 4-6-2 Type.; London and North-Eastern Railway, Cock O the North, 2-8-2 Type, and 4-6-2 Silver Link. In this paper Stanier declared his debt to Churchward. In the subsequent vote of thanks Gresley echoed Stanier's appreciation. Stanier also noted that 'streamlining may be something like that blessed word "Mesopotamia" to the old lady. At any rate it has good publicity value.
A far better precis was published in The Locomotive Magazine:
On 30 September W. A. Stanier, chief mechanical engineer of the London, Midland & Scottish Railway, gave his presidential address to the Institution of Locomotive Engineers, taking as his subject the progress of locomotive design during recent years. Whilst Stanier's paper at Blackpool, which is dealt with elsewhere in this issue, is devoted to the testing of locomotives, the presidential address was a review of recent developments. The improvement in trade and the rivalry of other means of transport had resulted in a general speeding up on the railways and he pointed to the ability of the steam locomotive not only to haul heavy trains at good average speeds, but to rival the internal combustion engined units. In addition there had been a general increase in the average speed of trains, with the need for a greater number of fast goods trains. He paid a generous tribute to what had been done on the London & North Eastern Railway by the Pacific locomotives of Sir Nigel Gresley when given a suitable path and load. This achievement was made possible because of the care taken and the experience shown in the boiler and engine design, and the skill and experience of those who built the locomotive to ensure reliability in service. Up to the present the general practice was to design locomotives on conventional lines. The boilers have usually been designed for a working pressure of 300 lb. per sq. in. or under, but there had been a marked increase in firebox volume, grate area, and an improvement in tube ratios. The engines have had cylinders designed with better steam passages and larger steam pipes and the valve gear has been arranged with longer valve travel.
On the Delaware & Hudson Railroad in the U.S.A. four progressive locomotives have been introduced, the latest of which have a working pressure of 500 lb. per sq. in. and it seemed from the way in which they have been put on the line, that some at least of them are not likely to be perpetuated. In Germany, France, America and England engines have been built with the Schrnidt-Henschel type of boiler having a closed circuit, with a pressure of 1,600 lb. to 1,800 lb. per sa. inch and producing steam from 850 lb. to 900 lb. per sq. in., but they have not progressed very far. The Winterthur high-pressure locomotive, which was tried on the Swiss Federal Railways, has a boiler of a special water-tube type. The engine is of the high-speed uniflow type with cam- operated poppet valves, a reduction gear drive of 1 :2.5 being provided, with a jack shaft and connecting rods transmitting power to the coupled wheels. The boiler pressure is 850 lb. per sq. in. Reference was made to the L.M. & S.R. turbine locomotive. A number of engines had been developed embodying the turbine as a power unit and most of these had been fitted with condensers, and in his opinion these auxiliaries had been the principal stumbling block to successful results. In collaboration with the Metropolitan-Vickers Co. the L.M. & S. had built their locomotive fitted with the Ljungstrom non-condensing turbine, similar to one which was running on the Grangesberg-Oxelosund Railway in Sweden. The Swedish engine was a 2-8-0 working heavy ore trains, whereas the L.M. & S. is a 4-6-2 for heavy and fast passenger trains. The turbine engine had been working regularly between Euston and Liverpool and back for twelve months, and had worked to Glasgow and back." Apart from a little trouble with the reverse turbine which had been put right, it had worked most successfully. Whilst a turbine is ideal for continuous working, it has still to be proved that it will operate effici- ently under the variable conditions of ordinary train working, and this, as Mr. Stanier pointed out, can only be ascertained by actual test, and one or two station stops may easily upset all the economies obtained in running. This engine was the first in this country to be fitted with roller bearings to all axles.
The reciprocating engine was eminently suited to meet the varying conditions which occurred in ordinary train working. The simplicity and flexibility of the ordinary reciprocating locomotive, combined with the fact that its intrinsic characteristic, as represented by the tractive effort speed curve, is exactly what it should be for railway work. It has a high value for a wide range of slow speeds when it is required for starting trains, and falls away at high speeds, when a large tractive effort is not required. This characteristic is the result of the expansive properties of steam, and of direct drive, unobtainable without complication from any other form of power, and makes the reciprocating locomotive almost unassailable against the progress of time and its competitors.
On the question of valve gears, Stanier stated that in spite of all competitors the Walschaert gear, introduced in 1844, still holds its own. It has the inherent advantage that any lost motion in the parts is reduced at the valve itself. It is simple to maintain, and can be arranged on the outside of the engine so that it is very acces- sible. In the latest arrangement on the L.M.S. 4-6-2 engines all the motion pins have needle roller bearings, except the return crank which has a radial ball bearing. This arrangement is expected practically to eliminate wear in the joints of the gear, and only requires greasing once a month and so reduces attention by the engine crew.
Every effort should be made to reduce weight, but in the search for lightness the use of aluminium heads for piston valves were not altogether successful owing to the grooves in the head becoming wider. Poppet valves operated by cams either through Walschaerts gear or through a rotary gear drive have been developed and have the advantage of lightness of valves, and on some railways are found to have advantages over piston valves.
A table shows boiler ratios, including free surface areas and their ratios for: LNER Silver Link (A4 Pacific); LMS Turbomotive Engine No. 6202; GWR Castle class; Nord 3.1171-90; German State Rly. 4-6·2; Canadian National 4-6-4 Class K.5.a and the Algerian Garratt 4-6-2 + 2-6-4
In England locomotive boilers are still of the conventional design, and the highest pressure is 250 psi. A great deal of investigation of the boiler proportions has been carried out, and there has been a great tendency to build boilers with larger grate areas and bigger fireboxes. Unfortunately the British load gauge restricts the size both of boiler and engine design, a width of 8 ft. 9 in. over cylinders and 13 ft. 3 in. high limits the proportions, and the weights on axles limit the weight of the various parts to much more modest dimensions than on many engines on the Continent and in America.
In America, many engines are running with water-tube fireboxes, and noteworthy examples are the Delaware & Hudson engines, already referred to, which have, in effect, a water-tube boiler joined to an ordinary boiler barrel. The Baltimore & Ohio R.R. have a number of engines fitted with a water-tube firebox, designed by the chief of motive power, Col. George Emerson, which has a water-tube wall on each side of the firebox. Both types are said to be free steaming boilers and are working at 350 psi or over. These fireboxes are made possible by the more generous dimensions of the U.S. load gauge.
These developments must be carefully watched, and all locomotive engineers are keenly following the boiler proportions ot engmes tnat are runnmg or contemplated. The following features deserve particular attention:-
(1) The grate area should be of sufficient size to ensure an average rate of combustion of about 50 lb. of coal per sq. ft. of grate per hour.
(2) There should be ample firebox volume to ensure combustion before the gases enter the tubes.
(3) Ample free area for both the superheater flue tubes and boiler tubes, and a suitable ratio for the superheated steam required without prejudicing the steaming properties of the boiler.
(4) A suitable evaporating heating surface and proportion of length to bore of tubes, so that the passage of gases is not unduly retarded through the tubes.
(5) Good air space through the grate; many modern grates have from 48 to 54 per cent. air space to grate area.
(6) Design of smoke box arrangement.
From a close examination of modern boiler design, particulars of the boiler proportions are very interesting. Fairly wide differences may be noted, which indicate that, within certain limits, the steaming and efficiency of a boiler will be quite satisfactory, and this fact is a great help, when it is realised that very often the design has to be modified to meet other important features. To enable boilers of the largest possible size to be built, it is necessary sometimes to use higher tensile steel plates than are normally used, and a number of railways have built boilers using a steel containing about 2 per cent. of nickel with the following analysis:-
Carbon 0.2% to 0.25%
Silicon 0.1% to 0.15%
Manganese 0.5% to 0.7%
Sulphur 0.04% t
Phosphorous 0.04 %
Nickel 1. 75% to 2.0%
Tensile: 34 to 38 tons per sq. in.
Yield: 17 to 19 tons per sq. in.
Elongation: 22 per cent. to 24 per cent.
Reduction in area: 50 per cent.
This material enables a reduction to be made m the thickness of the plates used in the design of the boiler, which results in a net reduction in the weight of a boiler, having about 29-30 sq. ft. of grate area, of 20 cwt. and a further reduction of 6 cwt. is obtained by using high tensile longitudinal and roof stays, a total decrease of 1 ton 6 cwt. No difficulty is experienced in flanging this material, and no detriment can be discovered as a result of electric arc welding certain parts, provided suitable electrodes are used.
The practice of electric arc welding on boilers has not developed far in England, although steady progress is being made. Up to the present no chief mechanical engineer has had courage to weld all the seams on a locomotive boiler, although in America it is quite usual for the steel firebox plates to be welded and not riveted. There is a fruitful field for research, as by eliminating rivets and lapped seams, weight can be saved and sources of weakness removed.
On the Continent a great deal of experimental work has been carried out in connection with boilers of the Velox and La Mont type. The Velox boiler has been developed by the Brown, Boveri Company, and advantages are claimed for this steam generator on account of the small space required, its exceptionally light weight, rapidity in raising steam and general suitability for service requirements.
The P.L.M. Co. have under consideration the conversion of a 4-6-0 locomotive to this type of steam unit. The La Mont steam generator is also of the water-tube steam unit type, and, roughly speaking, it is claimed that to give the same out-put as a conventional type of locomotive boiler the La Mont type would be about half the weight. Both of these water-tube boilers have a very high rate of steam production, and one of the most im- portant auxiliaries is the provision of a pump to ensure that satisfactory circulation is maintained. It may be that the future high-speed locomotive will depart from the simple type originated by George Stephenson, and we shall have a super steam raising unit supplying high-pressure steam to a small totally enclosed multi-cylinder high- speed engine on the lines of the Doble or the Swiss Locomotive Co.'s engine, which was tried a few years ago. One of the factors necessary for the success of such a machine would probably be a good water supply.
On the L.M.S. in recent years an effort has been made to improve the quality of the water supplied to the locomotives. A large number of water softeners have been installed, and are now being brought into service. The introduction of water softening in bulk has its inherent troubles. Many of the waters to be dealt with have a con- siderable permanent hardness, and this necessitates the addition of soda to remove this very undesirable feature, resulting in a softened water of an alkaline character, which invariably sets up a condition in the boiler causing priming. To avoid the high concentration of priming salts, it is necessary to blow the boiler down frequently, or alternatively, to ut every boiler with a continu- ous blow-down so that the concentration of prim- ing salts in solution does not exceed 180 grains per gallon. This means continuously discharging about two gallons of water per minute all the time an engine is working. This system has been introduced very largely in America, and the L.M.S. are now engaged in fitting a continuous blow- down on all engines, so that the fullest advantage can be taken of water softened down to zero hardness. It has been proved that unless zero hardness is provided, most of the advantage of water softemng is lost, due to corrosion, priming and other troubles.
By careful design and suitable loading the problem of high speed is not insurmountable, but combined with it is the problem of stopping distance. A train of seven coaches with an engine havmg a total weight of about 365 tons, will require something like 1,700 yards before it will come to a stand from 90 miles an hour on the level, this with a full application of the brake, and as the distant signal is usually not more than 1,200 yards in the rear of the home signal, high speed postulates a new set of running conditions. In America many railroads are equipped with an elaborate system of automatic train control and cab signalling apparatus. In England the G.W.R. is equipped on all its main lines with automatic train control of a simple form, which depends on a plunger on the engine being raised by a ramp in the track to operate an audible signal, and if the distant is on, the brake is partially applied at the distant signal. The L.M.S. are experimenting with a signal of the Hudd type that is, a magnet in the track operates an armature on the engine receiver unit which, through a relay, sounds a horn, and partially applies the brake. 'Whether any of these systems will help to speed up train working remains to be seen, but even with these devices functioning with the utmost reliability the problem of the distance required for making a stop still remains. The power brake as at present applied to the locomotive and coaching stock is of necessity limited to the amount that can be applied at slow speeds to avoid skidding the wheels, so that at high speeds it has very limited effect.
Streamlining has no material advantage at speeds under 60 m.p.h., but it does give increasing advantage above that speed. The important point with regard to wind resistance is that it increases in proportion to the square of the speed of the train. This means that the air resistance of a train running at 80 m.p.h. on a calm day is four times as great as it is at 40 m.p.h. or sixteen times as great as when the train is travelling at only 20 m.p.h. Streamlining may be something like that blessed word "Mesopotamia" to the old lady. At any rate, it has good publicity value. There is still much to be done and a wide margin to attack. The heat value of fuel and the efficiency of the locomotive as expressed by work done still leave something for us to do. Therev is ample evidence that the field for steam locomotives, for long distance working so far as the UK is concerned has still possibilities for further investigation.
Collingwood, G. (Paper 358)
New 4-8-4 type locomotives for the Chinese National Railways. 595-626. Disc.: 626-39.
Fifth Ordinary General Meeting of the Manchester Centre held in the Building of the Literary and Philosophical Society, 36, George Street, Manchester, on Tuesday, 31 March 1936, at 7 p.m.: chair being taken by Mr. R.C. Bond.
The engines were required for fast freight, passenger, and general services on the Chinese National Railways, the ruling grade of which was 1 in 66 and the sharpest curve 492 feet. A low grade of bituminous coal only was available, and the boiler was proportioned accordingly; this, of course, accounts for its large size and the very ample grate area provided. According to requirements, bar frames were employed, and it might be said that these two units-coupled with the weight conditions imposed-governed the general structure of the whole locomotive.
Weight was a considerable difficulty in this design, and all details during the drawing stage had to be carefully scrutinised to see that they were made as light as possible. The following examples of the measures taken:
(1) The coupled axles were hollow bored.
(2) The thickness of the plates and sections were reduced to a minimum, and lightening holes were machined in the plate work wherever possible.
(3) The platform1 plates were made of 4 mm. chequered plate, and instead of a riveted outside angle the plates were bent over in a folding machine.
(4) All spindles for operating gear were made of tubing.
(5) On the tender the plate-work was made of 8 m.m. copper bearing steel, to resist corrosion, and was welded throughout.
Discussion: R. Arbuthnott (626-7); E.M. Gass (627) queried of valve travel and high superheat. The adoption of a valve travel of 9in. was unusual, it would be of interest, therefore, if some diagrams of the steam distribution were pub1ished. It was an open question, he said, whether a travel of more than 7½in. was beneficial. Admitted the longer valve travel delayed the closing of the exhaust port, but there was a limit to this, in that insufficient steam remained to fill the clearance space between the advancing piston and the cylinder end. He remembered some diagrams in which the exhaust closure was fixed as late as 90° of the piston stroke for all points of cut-off. The records showed a distinct fall in pressure at the commencement of the admission period. Regarding the multiple throttle valve header in the smokebox, he asked if the poppets were on the saturated or superheated steam side. He thought the superheated side preferable, as the element tubes were then constantly charged and no time was lost in raising the desired degree of superheat. The gear for operating the poppets, comprising levers, brackets, compensator, and rods, mounted outside the boiler and then returning to some position on the firebox back plate seemed to be cumbersome as compared to the general practice of a rod passing direct through the boiler. The proportion of the superheating surface (approximately 25% of the total heating surface) was very high, the general practice being, he thought, about% of the tube heating surface only. He said he would like the Author to gixe the temperature of the superheated steam. It was interesting to hear, he said, that the compensation of all the engine springs, arranged in two groups, was very satisfactory.
Reply: provision had been made for indicating the engine, and no doubt particulars will be available for publication at a future date. The effect of the long valve travel is to have the maximum port opening over a long period both for the steam inlet and exhaust, and so obtain a free-running and efficient engine. In regard to the point about insufficient steam remaining in the cylinder to fill the clearance space at the end of the stroke, it should be pointed out that the valve events in this case correspond with those for short travel valves. The superheater header is constructed in two compartments, that is, a saturated and a superheated compartment. The elements are constantly charged with steam. After pissing through these elements, the steam is delivered into the superheated compartment where the supply to the cylinders is controlled by the poppet valves. This means that superheated steam is available right from the initial openinp of the regulator. In his opinion, the outside gearing for operating the regulator is one of the features of the multiple-valve type of header. It is a very simple arrangement of levers and rods, and needs far less shed maintenance than the usual regulator rod passing through the back-plate of the firebox. He agreed that it does not improve the looks of the engine. The temperature of the superheated steam is 750°F., and the type of superheater fitted was purposely selected to give this high degree of superheat. Mr. Rickards remarks on the large size of the exhaust passages. These were made slightly larger at the steam chest end and taper gradually to the bottom of the blast pipe. The blast nozzle is fitted with a jumper ring, as previously mentioned, and this regulates the blast, the beat therefore being practically normal.
G.M. Rickards (627-8) commented on exhaust passages; G.F. Horne (628-9) compensated springs; I.C. Forsythe (629) grease lubrication; R.C. Bond (629-30); Blundell (635-6) mud plugs, also noted problems at Sheffield where 22% of booked repairs related to sanding appartus; Selby (636-7)..
Mills, F. (Paper 359)
Girder stays for locomotive fireboxes. 640-51. Disc.: 651-4.
27th Meeting of the Western Australian members held in the Railway Institute, Perth, on Friday, 15 May, 1936, at 8 p.m.: chair being taken by Mr. W.A. Lampard.
Journal No. 134
Morse, H.M.R. (Paper 360)
Painting of North Western Railway coaching stock with particular reference to "peeling" and other common faults on steel panels. 659-703. Disc.: 703-23.
Fourth Annual General Meeting of the Indian Eastern Centre was held at Agra on Friday, 7 February 1936, the chair being taken by Mr. D. Cardew
Thompson, J.W. (Paper 361)
The taper boiler. 725-63. Disc.: 763-6. 26 figures.
Second Ordinary General Meeting held at the Institution of Mechanical Engineers, London, on Wednesday, 28 October, 1036, at 6.0 p.m., Mr. W.A. Stanier, President of the Institution, occupying the chair.
Locomotive draughtsmen are familiar with the lines of a locomotive boiler, but unless one has worked continuously at boiler work for a time there are many points which crop up, particularly in the higher-pressed boilers of today, which require more careful attention to their design, in view of the future probable high maintenance. This Paper is intended more as a guide to draughtsmen and engineers who are already familiar with boiler design, but lack the necessary knowledge of the process through the shops. In this work, however, it is intended to deal with the laying out anmd forming of the principal plates of a modern taper boiler.
Plate 1 shows an outline of a modern taper boiler which is made up of (A) Smokebox Tubeplate, (B) Cylindrical Barrel, (C) Dome made out of one plate, (D) Dome Top, (E) Dome and Top Feed Stiffening Plate, (F) Coned Barrel with horizontal bottom, (G) Outer Wrapper Plate, (H) Inner Wrapper Plate, (J) Throat Plate, (K) Coppcr Tubeplate, (L) Outer Back Plate, (M) Inner Back Plate, and (N) Throat Plate Stiffener.
Discussion: The President (W.A. Stanier 764): Unfortunately I have to leave to attend another meeting, but before I go you might like to have some expression of opinion from me with regard to the taper boiler, because 1 have been perpetrating taper boilers for some time. The Author illustrates this very clearly in Plate 27.
By tapering the big ring of the boiler, you obtain additional steam space, and, taking the other end on view you obtain an increased water-line for the steam to come off. Other advantages of the taper boiler are that at the front end, where you are often tied up for excessive weight, you can keep the weight down to within reasonable limits, and also, when the locomotive is going downhill, the water is kept on the crownplate of the firebox. Those are some of the points about the taper boiler which seem to me to make it desirable.
The Author has stated that the manufacturing difficulties are very easily overcome, and in fact the LMS works Crewe, have had no difficulty whatever in manufacturing taper boilers in just as satisfactory a way as other works. I must now ask you to excuse me, and I will ask Col. Collins to take the chair for the remainder of the meeting.
H. Chambers (763-4) comments were largely on the detailed aspects of boiler design, especially in its translation from drawings into practice. T. Lunt (764) There is one little point which had interested him namely the throat plate which was shown flat at the top. With some firms it was the practice to take the flat plate and put it over the blocks, and the outer edge is flanged round first. Some companies, however, made a joggle at the top of the throat of about 1in., with the result that when put in the die block it grips the plate and the other block coming through in the middle carries it down, so that this nipping action prevents the drawing on the plate going so far through, with the result that one can use slightly less allowance on the flat plate at the top to allow for the pulling through action which takes place with the parallel plate. On the other hand, this increase in size is quite a good feature, because it gives you a little more steam space on the top and also on the 4de. Where there is a definite line of projection coming round there is a little more space at the side for the ebullition of the steam and for the steam to get out into the top space. The author replied: there is always a certain amount of flat in the corners (see Plate 14) which has to be taken care of with a couple of short longitudinal stays. In flanging the throat, these two flats stop the plate from pulling. We do not have any trouble at Crewe from the plates pulling one side or the other. Mr. Lunt mentions that to overcome the difficulty the method of joggling is sometimes used. To my mind that is a bad method if it can be avoided, because by the breathing of the boiler during service, cracks are set up there. We have had experience of that with the old Claughton boiler. This method of flanging the throat was used in this case to bring in existing dies, also the press at hand had no centre ram as in the press on Plate 18. Short abstract in Locomotive Mag., 1936, 42, 345
Renwick, H.P. (Paper 362)
The most suitable passenger locomotive for intensive use and for long runs. 767-71. Disc: 771-806.
Second Ordinary General Meeting of the Western Branch of the Indian and Eastern Centre held at the Taj Mahal Hotel, Bombay, on Saturday 28 July 1934, at 6.0 pm., the chair being taken by Mr. R.C. Case.
Meeting at Buenos Aires, South America, on June 26th,
Second Quarterly Meeting of the South American Centre held at Buenos Aires, on Friday, 26 June 1936 when Paper No. 346, on Locomotive Wheels, Tyres and Axles, by E.S. Cox, published in Journal No. 128, which was presented before the Institution in London on 31 October 1935, was discussed. This was followed by a luncheon at Once Terminus Station of the Buenos Aires Western Railway, after which the party left at 2 p.m. in the 450 h.p. Diesel electric articulated coach for the Liniers workshops, where a tour of inspection was made, the party returning later to Buenos Aires.