Economical Traction for Special Services
THE steam locomotive for passenger and goods transport purposes has enjoyed such a long and hitherto unchallenged reign in all countries that it has come to be regarded as a firmly established part of all railway systems. With the rapid evolution of the petrol and Diesel engines, however, this supremacy has been challenged.
The advantages of the internal combustion engine are dealt with in the chapter “British Diesel Rail Coaches”, beginning on page 609. They are claimed to be compact, low first cost, lower fuel costs, absence of boiler, the ability to develop full power from the cold condition in a few minutes, the fact that no fireman is required in addition to the driver, and better all-
Although numerous petrol-
Numerous practical difficulties were encountered in the earlier attempts to adapt the Diesel engine to railway locomotive requirements, principally in connexion with engine noise, vibration, transmission, and controls, but all of these have been overcome satisfactorily. The question of the relatively higher rate of wear of the high-
At the present time, the Diesel engine may therefore be considered satisfactory for many locomotive purposes. The Diesel locomotives and rail-
The Diesel locomotive, at present, is normally made in much lower horsepowers and for smaller haulage efforts than the steam locomotive; it is therefore employed principally for local goods haulage and shunting or switching purposes on main line and narrow-
Since the present account is mainly confined to the smaller class of Diesel locomotives employed for shunting and goods haulage work, it may be of interest to give some general information relating to British makes of locomotive before proceeding to describe a number of typical commercial makes at present in use, both at home and abroad.
Disregarding the narrow-
The tractive efforts available for starting purposes range from 6,000 to 30,000 lb, and the locomotives will haul from 100 to 1,000 tons on the level, according to the size of engine fitted and the speed of working.
The usual wheel arrangement for the smaller shunting locomotives is the 0-
Several types of transmission systems are employed. In all examples, it is necessary to interpose some kind of reduction gear, since the driving wheels of the locomotive revolve at a much lower rate than the engine; moreover, for starting purposes and when hauling heavy loads it is necessary to have a much higher turning effort, or torque, at the driving wheels than is given at the engine's crankshaft.
The necessity for reduction gears is just as important in a high-
Methods of Gear-
The smaller Diesel locomotives are normally fitted with a friction type of clutch and a two-
This type of Diesel locomotive is thus built on a principle similar to that of the ordinary motor-
In the medium and larger sizes of Diesel shunting locomotive, these objections have satisfactorily been met by the substitution of the hydraulic or electrical systems for the mechanical gear transmission. The use of oil-
The electric transmission system consists in coupling the engine to a dynamo, or generator, and taking the electrical output from the latter to electric motors on the driving wheel axles. By means of suitable resistances controlled by simple switches it is possible to provide the driver with an easy and effective means of control for starting, accelerating, and stopping. The larger Diesel locomotives generally employ this electrical transmission system.
Compactness is another advantage of the Diesel locomotive. Since there is no boiler in front, a much better field of view is obtained from the driver's cab than would be possible in a steam locomotive.
The relative shortness of the high-
The Diesel engine is generally -
The water employed to cool the cylinder heads and barrels is in its turn cooled by means of a radiator, or radiators, placed in front so as to obtain the maximum cooling effect. A belt-
IN SERVICE ON THE LMS. The 200hp Davey Paxman Diesel engine of a Hunslet locomotive. The small compressor for supplying air to the brakes and be seen on the left side. Four engines of this type have been supplied to the LMS for shunting purposes.
The controls sometimes appear to be more complicated than those of the steam locomotive -
There are, of course, instruments that require an occasional glance; these include the oil pressure gauge, engine revolution meter, and vacuum gauge, and voltmeter and ammeter for locomotives having electrical transmission.
The starting of the high-
The smallest engines when cold are often started by hand with the help of a device for temporarily releasing the engine compression. In the larger engines electric glow plugs -
A small petrol engine of about 3 to 4 hp is sometimes fitted for starting the larger Diesel engines, though compressed air, supplied from a steel cylinder, may be used instead.
When the electrical transmission system is employed engine starting is a very simple operation. The driver merely presses a push-
A few representative Diesel locomotives will now be described. The Drewry narrow-
The engine and its radiator are mounted at the front end of the locomotive, as in automobile practice. It is provided with an electric starting motor having a sliding “Bendix” pinion, the teeth of which engage with similar ones on the rim of the engine flywheel.
The various adjustable parts of the engine, as well as the fuel pumps, oil filters, water-
A range of Diesel locomotives has been built by the Hunslet Engine Company of Leeds, including both small and large types. The former are built in the 20, 30, and 40 hp sizes and use two-
The arrangement of the engine and radiator is the same as in the small locomotive described above. A two-
The small Hunslet engines all use the 0-
One of these locomotives, which is of the 0-
The engine is a six-
Hauling 700 Tons
The governor control is operated in conjunction with the lubricating oil pressure, so that, should the latter fail in service, the governor will be non-
The camshafts, set on either side of the cylinder heads, are chain-
Perhaps the most important of the auxiliaries is the equipment for starting. This is carried out automatically, the power being derived from a two-
A compressor is arranged to supply air for the “Westinghouse” straight air brake, and to feed various auxiliary controls, such as the rocking brake and air whistle.
The cab is of a new design and gives an exceptionally good look-
The weight of the locomotive is 30 tons, and the gearbox gives speeds of 4, 8, and 13 mph, the respective tractive efforts being 14,400 lb on lower gear, 7,200 lb on second gear, and 4,400 lb on top gear.
This locomotive is capable of hauling loads up to 700 tons. Other Hunslet locomotives supplied to the LMS Railway include a 150 hp model fitted with an eight-
The LMS has also introduced into service a Diesel shunting locomotive built by Messrs. Harland and Wolff of Belfast. This six-
No. 7057 is designed for control by one man, and has the normal driver’s cab provided with duplicate controls for easy operation from either side of the cab, in which there are windows to provide a clear view of the track both backwards and forwards.
CAPABLE OF HAULING 700 TONS, this Hunslet Diesel shunting locomotive weighs 30 tons and has a Davey Paxman 200 hp Diesel engine. The gearbox gives speeds of 4, 8, and 13 mph. This locomotive operates on the LMS Railway.
The engine is started by compressed air stored in reservoirs at a pressure of 375 lb per sq in. To facilitate starting from cold, a glow plug, heated electrically from the accumulators, is fitted in each cylinder.
The engine is of the airless injection type, and has a rotary scavenge blower, gear-
Each cylinder has a separate fuel pump supplying fuel under pressure to the automatically operated fuel valves in the cylinder heads.
The transmission is by means of a hydraulic coupling to a two-
Messrs. Hawthorn, Leslie & Co Ltd, of Newcastle, have built a number of Diesel shunting locomotives. One of these was supplied to the Air Ministry for shunting and haulage work over a six-
The same firm, working in conjunction with the English Electric Company, Ltd, has produced an interesting Diesel shunting locomotive. The general particulars are as follows: gauge 4 ft 8-
ELEVATION showing the general arrangement of an Armstrong Whitworth 880hp oil-
This locomotive has a 300 hp six-
One of its most striking features is its availability for continuous service. It can remain at work for practically twenty-
A similar locomotive has been in service for some time on the LMS, and has satisfactorily undertaken all types of shunting work; it has been tried in the shunting yards at Crewe, Rugby, Beeston, Toton, Camden, Salford, Healey Mills, Wakefield, and Carlisle.
The equipment is housed with a view to accessibility and ease of replacement. The superstructure is divided into three compartments: driving cab, control compartment, and engine compartment. In the cab there are two separate driving positions, one on either side of the cab, each having a driving control handle, reversing handle, and brake controls.
In the control compartment all control apparatus is mounted on a self-
The Diesel engine and generator set are mounted in the engine compartment on a three-
Electric Torque Controls
The two driving motors are mounted on the two outside axles and are supported by brackets from the locomotive under-
The cab is of the fully-
In this locomotive is embodied the first application of electric torque control. The general principle of this system is that the Diesel engine speed is held to a pre-
The Diesel engine is one of a series of medium speed engines developed and standardized for traction and industrial work. These engines are made with six, seven, or eight cylinders, and develop 300, 350, or 400 hp respectively at 600 rpm. Each cylinder has a bore of 10-
A vertical water cooler is mounted at one end of the locomotive, a centrifugal pump being driven from the camshaft. In addition, the lubricating oil is circulated by means of an engine-
The superstructure is of steel, housing completely the radiator, engine and generator, control framework, and all auxiliary apparatus. The roof is made detachable and in sections to facilitate removal of the power unit and auxiliaries.
Dual brake equipment is fitted, comprising straight and automatic airbrake and vacuum-
THE CEYLON GOVERNMENT RAILWAYS employ this 20-
The sanding gear is hand controlled from either side of the driver’s cab. Four sand boxes are provided, to deliver sand in front of the leading wheels and behind the trailing wheels. The locomotive began running in trial service on the LMS Railway in April, 1934. In eight months of continuous service the engine running time aggregated 4,000 hours. An opportunity was then taken to examine the conditions of the engine and electrical transmission, and the whole unit was found to be in excellent condition. In normal shunting conditions the consumption of fuel and lubricating oil averaged two to three gallons of fuel and one pint of lubricating oil per hour.
After the inspection, which lasted only a few days, the locomotive was returned to further service duties in the shunting yards of the LMS Railway.
Messrs. Armstrong Whitworth, Ltd, have produced, at their Scotswood Works, Newcastle-
At one end of the range is a 15-
Another range of shunting locomotives made at the Scotswood works included a 40-
After this, some six weeks’ trial running in yards of the Southern Railway was undertaken, and then a period of service in industrial yards. The outcome of the working of this locomotive was the supply to the LMS of a machine of a similar type.
A Versatile Locomotive
It was then decided to prepare a machine capable of passenger, goods, and general service operation, and the demonstration model was a 2-
The success of this class of Diesel locomotive has led to the decision to prepare two 5 ft 6 in gauge examples, for trial on the Ceylon Government Railways. In addition, an order has been secured from the North Western Railway of India for two 1,300 bhp 4-
The firm of William Beardmore, Ltd, has made a number of Diesel engines for passenger and shunting purposes. It supplied the engines for the 2,660 hp Canadian National Diesel electric trains.
One interesting shunting locomotive is a double-
A LIGHT SHUNTING LOCOMOTIVE built by Armstrong Whitworth, and weighing 15 tons. It is equipped with an Armstrong-