SPACIOUSNESS AND COMFORT are the keynote of the driver’s compartment in this AEC Diesel Rail Coach. As the engine is placed within the chassis, the view through the wide glass windows is uninterrupted.
DURING recent years the local, and to some extent the main line railway services have experienced growing competition from road passenger transport; thus a large number of passengers have been lost by the railways. One reason for this state of affairs is that the petrol and oil-
The road motor coach or omnibus is usually designed so that the weight of the chassis and body is kept down to the lowest possible figure, whereas with the steam vehicle, owing to the type of construction employed, a considerably greater weight is needed for the same number of passengers carried. Thus in the instance of one particular road coach the weight of the vehicle works out at 300 lb for every passenger carried. On the other hand, a certain type of steam coach fully occupied gives a weight of 1,000 to 1,200 lb for each passenger.
Evidently, therefore, with the existing pattern steam coaches, it cannot be so economical to carry a person by rail as by road, for not only is the steam coach from three to four times as heavy as a road motor vehicle, but also its first cost is considerably higher.
It is well known to engineers that the steam locomotive engine is far less efficient than the petrol engine, for it will generate only from one-
The disadvantages of the steam coach are thus rather numerous. It is considerably heavier, and therefore requires more horse-
FRONT VIEW of a Rail Coach belonging to the Great Western Railway, showing the exterior of the driver’s cabin.
THE STREAMLINED NOSE of a Great Western Rail Coach, showing the steps and entrance to the driver’s cabin. The driver’s seat is partly visible.
In view of the various advantages of the internal-
The railway engineer knows that if rail passenger coaches are made in a manner similar to those used on the road services, a large saving in the weight to be hauled is made possible. Further, by using the petrol or Diesel engine instead of the more cumbersome steam engine, a considerable economy in the fuel costs can also be effected.
Another important advantage results from the operation of road vehicles on railways. The substitution of plain flanged wheels and smooth, straight railway tracks for road conditions results in a marked reduction in the driving effort required to haul these vehicles on the rails; there are no road inequalities, rough surfaces, or steep hills to negotiate.
Everything, therefore, appears to favour the use of railway coaches built on modern road vehicle lines and propelled by similar engines. In their first cost, and in running costs, they have the advantage of steam coaches; and they should be able to compete successfully in running and maintenance costs with road passenger vehicles. Incidentally, also, the smaller Diesel rail coach is much more economical than almost any form of electrically propelled train, because of the high capital charges for track electrification.
In these circumstances it is not surprising to learn that several British firms have concentrated upon the design and manufacture of Diesel rail coaches, and that several satisfactory types are now in use at home and abroad. There are also a number of Continental and American rail-
In this connexion it has been definitely established that for the transport of from forty to a hundred persons the Diesel rail coach is in most respects superior to the steam-
The most favoured types of British Diesel rail coaches are those designed for the accommodation of from forty to seventy passengers at cruising speeds of fifty to sixty miles per hour. The overall lengths of these rail coaches range from about forty to sixty-
Some idea of the relatively low fuel costs may be obtained from the statement that the smallest rail-
The designs of all the British Diesel rail-
The controls include levers for the gear-
The braking arrangements have been carefully considered, for, owing to the high rail speeds attained, it becomes essential to be able to bring the cars to rest as quickly and as smoothly as possible. The vacuum brake appears to be the most suitable for this type of vehicle, and it is therefore to be found on most of the different makes of rail-
AT SPEED ON THE GREAT WESTERN RAILWAY. This AEC Rail Coach has excellent powers of acceleration, and is capable of a maximum speed of over seventy miles an hour. An express rail-
An interesting feature of the Diesel rail-
The advantages and the principal features of British rail-
The first of the rail-
The AEC rail-
The car has the same type of Diesel engine as that employed on motor-
The seating accommodation is arranged for sixty-
The AEC rail-
The engine is connected to a special design of gear-
The Wilson gear-
AN ARMSTRONG WHITWORTH RAIL-
From the reverse gear-
The axles rotate in roller bearings within their axle boxes. The chassis frame weight is transmitted through the usual pattern laminated springs to the tops of the axle boxes; the latter slide in horn plate guides as in ordinary locomotive practice. The brakes, instead of being of the conventional rim type of shoe brake, are internally expanding brakes of the automobile pattern working inside brake drums.
The braking force is obtained from the pistons of vacuum cylinders; two such vacuum cylinders are mounted on each bogie. The vacuum required for these cylinders is maintained by two exhausters. One of these is mounted on the top of the gear-
The car is electrically lighted, a large-
A larger type of AEC rail-
Before dealing with the transmission and other technical details, it will be of interest to mention some general facts regarding the vehicle and its general performance.
LEAVING NEWCASTLE CENTRAL STATION. Armstrong Whitworth rail-
On its demonstration trials one of these rail-
The general arrangement of this rail-
One of the Diesel engines, with its transmission units, is arranged in an accessible position on one side of the chassis, while the other is placed in a similar position on the other side. To provide ample cooling when travelling in either direction the radiator is set diagonally and the air is drawn through it by means of a cowled fan; this air is collected by one or other of a set of louvers. A hinged plate, automatically operated, ensures that the air stream from the appropriate louvers is directed towards the cowl.
The coach arrangements include a compartment at each end in the “nose” of the body for the driver, with space for luggage in the larger one of these compartments. The hot water supply in the lavatories is ingeniously provided by utilizing the exhaust gases of the engines; this apparatus is the silencing system also, the gases then passing through an exhaust pipe in the roof. There is a buffet, divided across its centre by a counter with four seats facing it.
The two passengers’ saloons are divided by the gangway connecting the two central doors and are fitted with forty fixed seats and with removable tables. The electric lighting is arranged to give a soft diffused effect. Tubular lights with two bulbs are fitted on the side panels above each seat and the same type of lamp is used down the centre of the roof. Ventilators for extracting the air are placed on the roof and above the windows. Electric fans are provided in the buffet compartment, and a heating system is also installed in the saloons, buffet and driver's compartments. Specially designed heaters are used for this purpose.
Armstrong Whitworth, Ltd, have built several types of Diesel rail-
In the two smaller rail-
It has been the aim of the manufacturers to ensure that maintenance can be carried out by the normal staff of a railway running shed, and no features are incorporated which are not within the experience of the modern railway workshop using road transport as an ancillary service. For this reason they have avoided the ultra-
The ABE (patented) transmission is so simple that it requires practically no attention in service. It eliminates the usual starting motor and charging and lighting generator. What little attention it requires in service is of a mechanical nature and can be done by the ordinary locomotive shed or carriage staff. Major repairs to the transmission can be carried out by the train lighting staff or by the existing locomotive works electrical department. This simple electrical transmission has a life at least twice that of any mechanical gear, even when the latter is protected by a hydraulic gear and is self-
Bogies of orthodox but light construction are employed. Great care has been taken in the design of the whole vehicle, including the body. The aims have been reliability, safety, and avoidance of high maintenance costs which might follow excessive weight cutting.
The general particulars of the rail-
Length over body: 52 ft 6 in
Maximum width: 8 ft 11½ in
Height above rail level: 11 ft 11¼ in
Bogie wheelbase: 7 ft 0 in
Distance between bogie centres: 30 ft 0 in
Diameter of wheels: 2 ft 9 in
Total weight in working order with 95 bhp engine: 17 tons 13½ cwt
Maximum axle load with car loaded (with smaller engine): 5½ tons
Total weight in working order with 140 bhp engine: 18 tons 17 cwt
Maximum axle load with car loaded (with larger engine): 6 tons
A most interesting feature of the design is perhaps the effective streamlining of coach ends and sides, which are scientifically proportioned to reduce air resistance to the minimum compatible with making full use of the coach length and width. The tare weight per passenger seat is as little as 0.31 ton or 0.25 ton, according to the number of seats provided.
A LEYLAND DIESEL RAIL-
The body provides an example of light road-
The exterior is panelled in 18-
Coach heating is by means of a small radiator through which passes some of the engine cooling water; a belt-
THE BRAKES and hydraulic shock absorbers of the Leyland rail-
TRANSMISSION UNIT and axle of the Leyland rail-
RESEMBLING A MOTOR CAR. Another view of the transmission unit, showing also the springs and a brake drum.
The power unit comprises an Armstrong-
The 95 bhp and the 140 bhp Armstrong-
The control fitted to this rail-
THE CHASSIS of the 130 hp Leyland Diesel rail-
A departure has been made from the usual railway type of braking, in the adoption of Ferodo-
AN END VIEW of the chassis of the Leyland Diesel rail-
The English Electric Company’s rail coach, designed primarily for branch-
The rail coach is fitted with a six-
The engine is direct-
The coach has five compartments -
The interior finish of the passenger compartment is of polished mahogany, with mahogany mouldings and chromium-
At the trailing end of the coach the partition separating the passenger and driving compartments is of glass from above the waist-
The coach is provided with a vacuum brake operating on all wheels. A screw-
THE GENERATOR AND CONTROL PANEL of an “English Electric” Diesel-
The engine compartment requires no attendance during running. The vehicle is arranged for one-
Driving a Diesel rail coach is simpler than driving a road motor vehicle, as there is no steering wheel.
The engine is started by operating a push-
Preventing Engine Overload
Excessive overload currents are prevented by the arrangement of the generator windings and by control of the excitation; and thus the engine itself cannot be overloaded. The full power output of the generator is automatically maintained constant over a wide range of train speed; it is therefore unnecessary for the driver to watch any instruments while driving.
A set of signal lights, consisting of two red and two white lights, is provided in each driving compartment. The white lights indicate that the pressure of the lubricating oil is adequate, and that the water circulation is correct. The red lamps glow to give a warning signal in the event of failure of oil pressure or of water circulation, and also to indicate when the engine is shut down.
A rail coach of this type has been in operation under service conditions on various sections of the LMS Railway system. The first period of running began in October, 1933, on the Weedon-
THE DRIVER’S CONTROL in the cab of a Diesel Electric locomotive.
Subsequently the coach was coupled to a standard railway trailer coach and put into service on the Watford-
The heating arrangements are interesting. A low-
Another interesting design of Diesel rail coach is that constructed by Leyland Motors, Ltd, for the London, Midland and Scottish Railway. This is a lightly built single-
The coach has only two axles, one of which is power-
Before describing the transmission system, it may be of some interest to refer to the performance of this small rail coach, expressed in its acceleration figures. In view of its relatively high power and light weight -
Reverting to the subject of the transmission, the employment of the hydraulic torque converter is a big factor not only in the attainment of the very high acceleration of this rail-
It should be understood that this torque converter is not the same as the “fluid flywheel”, referred to on the early part of this page; for it replaces the latter as well as the pre-
Reversing Gear Mechanism
From the hydraulic torque converter the power is transmitted by means of a propeller shaft through a reversing gear mounted in the casing of the driven axle. Spiral bevel pinion wheels are used to take the drive from the propeller shaft to the axle. The reversing gear mechanism is actuated by means of a double-
A larger type of rail-
The efficiency of modern Diesel rail-
THE DIESEL LOCOMOTIVE has proved itself to be of value in freight service as well as in passenger traffic. The above photograph shows a six-
“Diesel Shunting Locomotives” on this website.