DIESEL, OIL-ELECTRIC AND MISCELLANEOUS TYPES The oil-electric locomotive is an electrically operated locomo tive having self-contained equipment for generating the required electrical energy. It utilizes an internal combustion oil engine as prime mover, transforms the power there developed by means of a generator and applies the resulting electrical energy through motors geared to the driving axles.
While practically all steam reciprocating engines to-day are of the double-acting type for the express purpose of increasing effi ciency and reducing size, weight, friction and cost, per unit of power output, and which provides power units of great capacity within certain plant or roadway clearance and weight limitations, the great majority of the internal combustion units are single acting, due to the high temperature stresses requiring free ex pansion and the elimination of stuffing boxes. Some experimental work is now under way toward the development of double-acting oil engines for marine service, and it is probable that the evolution of the gas and oii engine will not only be along the lines of the simple four-stroke cycle principle, but also as double-acting, multiple-expansion and direct drive. Until this is accomplished, and greater hauling capacity can be produced when accelerating, and for sustained speed in relation to starting power, and per unit of weight and space, probably little will be done in the application of the internal combustion principle to locomotives of great power in the United States where the Diesel principle, up to the present time, has been applied to the smaller rail motor car or locomotive units ranging from 30o to 75o h.p. and in combination with elec tric, in preference to direct drive.
The latest development along these lines is probably the West inghouse oil-electric rail car, which makes use of the Westing house-Beardmore oil engine as the prime mover. For a 33o h.p. capacity unit this engine weighs about 21 lb. per horse-power. It is of the vertical, single-acting six-cylinder, four-stroke-cycle, solid injection type, with a speed range of from 30o to Boo. r.p.m. for the development of 33o horse-power. The mechanism of this engine is simplified, in that the pump for injecting the oil into the combustion chamber is driven from the crank shaft and controlled by a variable-speed type of governor. The engine is water-cooled
by means of a centrifugal type water pump driven from the crank shaft. An oil pump provides the pressure type of lubricating sys tem. The Diesel engine oil, lubricating oil and cooling water pumps are integral with the engine proper. The engine is coupled to a 23o kw. 600 volt direct current, direct driven generator which is provided with fan ventilation for the armature and fields. An auxiliary generator of 64 volts is mounted at the commutator end of the main generator for the purpose of charging the 64 volt battery.
The traction motors are of the self-propelled general Westing house type, equipped with a dual ventilating system for the elimi nation of dirt and dust from the motor commutator. This engine is being substituted for gas-electric units on account of the abil ity to make use of the Diesel engine oil, or a cheaper grade of fuel, in the ratio of i to 21 or 3 in the normal oil market, as compared with gasolene. By reason of the higher efficiency of the cycle it converts a greater number of B.T.U. into useful energy, and from a safety standpoint Diesel oil is much less inflamma ble than gasolene and greatly reduces the fire risk. It is also claimed that the efficiency does not fall, under reduced loading, to anywhere near the same extent as that of the gasolene engine. Oil-electric locomotives have been constructed individually or jointly in the United States by the Ingersoll-Rand Company, the General Electric Company, the American Locomotive Company and the Westinghouse Electric and Manufacturing Company, and these units have been used principally in connection with switch ing service. The Canadian National railways have, during the past two years, gone quite extensively into the use of the oil electric type of motor cars. They will also shortly have in service an oil-electric locomotive of 2,500 h.p., nominal rating. The oil engines for this locomotive were designed and built by the Wm. Beardmore Co. Ltd., and the electrical transmission and control equipment by the Westinghouse Company. The two units of the locomotive will weigh approximately 320 tons and develop a tractive effort at starting of 125,000 pounds.