RAILWAY MOTOR-CARS
In the early days of railway construction vehicles were used which combined a steam locomotive with an ordinary passenger carriage. After being abandoned for many years, the "steam carriage" was revived, in 1902, by the London and South Western and Great Western railways for local service and the handling of passenger traffic on branch lines. Since that year rail motor-cars have multiplied; some being run by steam, others by petrol engines, and others, again, by electricity generated by petrol engines. The first class we need not describe in any detail, as it presents no features of peculiar interest.
The North Eastern has had in use two rail-motors, each fifty-two feet long, with a compartment at each end for the driver, and a central saloon to carry fifty-two passengers. An 80 h.p. four-cylindered Wolseley petrol motor drives a Westinghouse electric generator, which sends current into a couple of 55 h.p. electric motors geared to the running-wheels. An air compressor fitted to the rear bogie supplies the Westinghouse air brakes, while in addition a powerful electric brake is fitted, acting on the rails as well as the wheels. The coach scales thirty-five tons.
The chief advantage of this "composite" system of power transmission is that the engine is kept running at a constant speed, while the power it develops at the electric motors is regulated by switches which control the action of the armature and field magnets. When heavy work must be done the engine is supplied with more gaseous mixture, and the generators are so operated as to develop full power. In this manner all the variable speed gears and clutches necessary when the petrol motor is connected to the driving-wheels are done away with.
The latter system gives, however, greater economy of fuel, and the Great Northern Railway has adopted it in preference to the petrol-electric. This railway has many small branch lines running through thinly populated districts, which, though important as feeders of the main tracks, are often worked at a loss. A satisfactory type of automobile carriage would not only avoid this loss, but also largely prevent the competition of road motors.
The car should be powerful enough to draw an extra van or two on occasion, since horses and heavy luggage may sometimes accompany the passengers. Messrs. Dick, Kerr, and Company have built a car, which, when loaded with its complement of passengers, weighs about sixteen tons. The motive power is supplied by two four-cylinder petrol engines of the Daimler type, each giving 36 h.p. These are suspended on a special frame, independent of that which carries the coach body, so that the passengers are not troubled by the vibration of the engines, even when the vehicle is at rest. The great feature of the car is the lightness of the machinery—only two tons in weight—though it develops sufficient power to move the carriage at fifty miles per hour. After travelling 2,000 miles the machinery showed no appreciable signs of wear; so that the company considers that it has found a reliable type of motor for the working of the short line between Hatfield and Hertford.
Since one man can drive a petrol car, while two—a driver and a stoker—are necessary on a steam car, a considerable reduction in wages will result from the employment of these vehicles.
Engineers find motor-trolleys very convenient for inspecting the lines under their care. On the London and South Western Railway a trolley driven by a 6–8 h.p. engine, and provided with a change-gear giving six, fifteen, and thirty miles per hour in either direction, is at work. It seats four persons. In the colonies, notably in South Africa, where coal and wood fuel is scarce or expensive, the motor-trolley, capable of carrying petrol for 300 miles' travel, is rapidly gaining ground among railway inspectors.
Makers are turning their attention to petrol shunting engines, useful in goods yards, mines, sewerage works. Firms such as Messrs. Maudslay and Company, of Coventry; the Wolseley Tool and Motor Car Company; Messrs. Panhard and Levassor; Messrs. Kerr, Stuart, and Company have brought out locomotives of this kind which will draw loads up to sixty tons. The fact that a petrol engine is ready for work at a moment's notice, and when idle is not "eating its head off," and has no furnace or boiler to require attention, is very much in its favour where comparatively light loads have to be hauled.