GIANT LOCOMOTIVE

Evening Star, Issue 23292, 14 June 1939, Page 4

GIANT LOCOMOTIVE

DEVELOPMENT IN ENGINE CONSTRUCTION MANY NEW DEVICES INCORPORATED DESIGNED ESPECIALLY FOR HEAVY WORK Designed for heavy duty, the first of the six new KB type of locomotives which are being completed at the Hillside Railway Workshops has been completed. During the past two days the monster engine has been undergoing trials in the shunting yards and on the line between Dunedin and Mosgiel, preparatory to being despatched to Christchurch. Constructed for heavy freight or passenger work, the engines will be used on the Midland line between Christchurch and Otira, where there are some very difficult gradients, particularly in the mountains between Springfield' and Arthur’s Pass. Heavy goods traffic is a feature of this line, and with the use of the new engines this traffic should be handled much more economically than in the past. For some time past the department has been strengthening all bridges on the line, a necessary procedure so that engines the weight of the KB’s might safely negotiate them. These locomotives have a total weight in working order of 145 tons, and, following modern designing practices, are built on the streamlined principle. They have two cylinders,. 20iu in diameter, with 26in stroke piston valves actuated by Walschaert valve gear and working a boiler pressure of 2001 b to the square inch. With a total wheelbase of 62ft and an overall length of 70ft the KB’s are a considerable advance on any locomotive yet operated on the New Zealand railways. . Moreover, these engines possess many features of interest inasmuch as they are equipped with every latest device for improving economy and efficiency, keynotes of design in up-to-date railway steam motive power practices.

TRACTION FROM A “BOOSTER.” In order to obtain the maximum effort from the locomotives roller bearings, housed in dust-proof axleboxes, have been fitted to all axles. To increase still further the tractive capacity of the KB’s an auxiliary engine is incorporated in each locomotive in the trailing truck. This auxiliary, or “ booster ” engine, consists of a simple two-cylinder geared engine which when required is thrown into mesh with a sprocket on the rear axle of the trailing bogie, thus turning the latter into an actual motive power unit. Theoperation of the “ booster ” is partly automatic. When the loading of the locomotive begins to appear beyond the capacity of the main engine in climbing heavy gradients, the driver engages the “ booster ” with a latch lever, providing an increase of tractive effort amounting from 20 to 25 per cent. The provision of this small auxiliary enables the locomotive to haul economicaC loads over the whole section —‘loads which in the past have been restricted through the gradients. ECONOMY THE KEYNOTE. Another economy device fitted to the KB’s is the AC FT feed water heater, which provides hot feed water for the "boiler while the engine is in motion. 'Normally, boilers are fed with an injector, but in the KB’s the water from the tender tank is drawn off by a feed pump Which delivers the cold water to a steel drum, or heater chamber, where it is brought in contact with a percentage of exhaust from the engine blast pipe. The hot water then returns to the pump which finally discharges it, de-oi)ed and practically purified, into the top of the boiler at a temperature of 220 deg Fahrenheit—Bdeg above normal boiling point. The effect of this pre-heating is to bring about a saving in coal consumption of from 10 to 12 per cent., less heat being required to convert the water into steam. Also a saving in water of about the same amount is effected by the use of the equipment. To obtain the maximum amount of available heat from the coal and to improve the circulation of water in the boiler two thermo syphons are welded into the firebox.

The KB’s carry a high degree superheater, with which is incorporated a multiple valve 'regulator which gives the advantages of accuracy of control. While superheating itself has been in vogue in New Zealand" for many years, an improvement has been added in the fofm of a targential steam drier fitted in the steam dome. This drier ensures that dry steam will reach the superheater, the result being a higher degree of superheat, and therefore greater coal saving, Braking is on the Westinghonse compressed air system of the most modern design. High pressure air is obtained from a pair of vortical compressors situated one on each side of the smokebox and partly concealed by the streamline casing. The engine lias attracted considerable attention during the period of its trials, and many references to the marked changes in railway engines in recent years have been made. Nothing like the KB’s has been seen in New Zealand before; the nearest approach being photographs of the new giant engines now in use on the Canadian and America railways. All those who have been in any way responsible for the construction of tile locomotive are deserving of the highest praise. It is a triumph of New Zealand manufacture. The remaining five locomotives are expected to be delivered at the rate of one a month up till December.