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The New Zealand Railways Magazine, Volume 2, Issue 5 (September 1, 1927)

Increased Locomotive Efficiency

Increased Locomotive Efficiency.

Standardisation of locomotive types is being steadily pursued by the German railways, but the door is still being left open to experiment in the locomotive field by the Berlin authorities, and there is no intention of adhering slavishly to the standard types of engine which are being developed in the interests of efficiency and economy.

In furthering their search for increased locomotive efficiency the German railways have this year introduced a new turbine locomotive of the “Pacific” type, developing 2,500 horse power, and capable of drawing heavily laden passenger trains at speeds of up to 75 miles an hour. In this latest experimental machine, two surface condensers are placed on each side of the boiler, a suction draught fan being situated on the inner side of the smoke-box door for the ejection of waste gases. Two single-stage air-suction steam ejectors serve to remove the air of the condenser, while removal of the condensate water is effected by a pump directly connected to a piston feed-water pump.

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The turbine of the new German locomotive is placed above the engine bogie, and transmits its power by means of a double reduction gear through connecting rods to the driving wheels. The forward drive and the backward drive turbines are situated in the same housing. The total wheelbase of the locomotive is 36 feet 6 1/2 inches, and oflocomotive and tender 69 feet 9 inches. The total heating surface is 2,269 square feet, and condenser surface 2,379 square feet. The tender is mounted on two four-wheel bogies, and has an overall length of 37 feet 8 3/4 inches. The water tank has a capacity of 1,138 gallons, and the coal bunker six tons. The weight of the locomotive in working order is 114 1/2 tons, and of engine and tender 189 1/2 tons. Designed to draw heavy trans-Continental expresses between Berlin and the Belgian border at an average speed of 62 miles an hour, the new turbine locomotive is, at present, being subjected to most exhaustive trials.

Here at Home, locomotive development has received a stimulus by the introduction on the London, Midland and Scottish line of three “Garratt” 2–6–0x0–6–2 articulated engines of an especially interesting type. These locomotives have a grate area of 44.5 square feet, and 2,637 square feet of heating surface. Coupled wheels are of 5 feet 3 inches diameter, and bogie wheels 3 feet 3 1/2 inches diameter. The overall wheelbase is 79 feet 1 inch, and the total weight of each locomotive, with 7 tons of coal and 4,500 gallons of water, is 148 tons 15 cwts. At 75 per cent. of the boiler pressure (190 lbs.) the tractive effort is 40,260 lbs., and at 85 per cent.45,260 lbs. Tractive power is 282.5 lbs. per 1 lb.M. E. P. in cylinders. One inside and two outside cylinders are provided, of 18 1/2 inches diameter and 26 inch stroke. The new L. M. & S. “Garratt” type locomotives are the first articulated machines to be utilised by the Home railways in main-line service, and their utilisation promises to extend considerably in the future. A somewhat similar type of “Garratt” machine, it may be noted, has for some months been employed with success by the London and North Eastern line for “banking” purposes in the Wath mineral marshalling yards.