POWERFUL LOCOMOTIVES

Otago Daily Times, Issue 23830, 9 June 1939, Page 3

POWERFUL LOCOMOTIVES

DESIGNED FOR HEAVY DUTY CONSTRUCTION AT HILLSIDE The first of the six new KB type locomotives which are under construction at the Hillside Railway Workshops is now completed and will probably undergo its trials on Monday next. These powerful engines are suited for heavy freight or passenger work, and they will be used principally on the Midland route between Christchurch and Otira, on which some particularly difficult grades are encountered. For some time past, the Railways Department has been carrying out a comprehensive programme of work on this line, an important feature being the. strengthening of the bridges which hitherto were too light to bear an engine of the weight of the KB type. Streamline Principle The locomotives are being built on the streamlined principle, and in this respect the Railways Department has followed the trends of modem designing practice in England. America, and, more recently, Australia. A further departure in the construction of the new KB’s is the complete fitting, even to the driving wheels, of roller bearings. This also is in conformity with the most up-to-date ideas. The KB engines will have a much greater tractive effort than -those of the same type at present running in the North Island. To cope with the heavy loads over two or three severe grades between Arthur’s Pass and Springfield, the South Island KB’s will be fitted with “ boosters.” A “ booster ” is something in the nature of an innovation for New Zealand—it only recently made its appearance in Australian engines. The “ booster ” is a conversion of the four-wheeled truck under the firebox into an extra steam-power unit, which is brought in to assist or “ boost ” the engine proper over heavy grades. Thus, when a train begins to climb a grade at about 30 miles an hour, the “booster" automatically cuts in and is in use till the grade is climbed, after which it automatically cuts out, and runs free-wheel. The tractive effort of the K engine is 30,8151 b, but the extra tractive effort afforded by the “ booster” is 64701 b, or an increase of 21.6 per cent. This will allow of a tractive load of about 560 tons over the grades referred to, against 280 tons, which is at present being hauled by the general utility “Ab ” engine. Thus it will be possible to run one train where at present two are operating. The Original Type The present KB engine is the second type to carry this classification. The original K’s were the first engines to be constructed for express train work in New Zealand. They were built by the Rogers Company of America, and were of the 2-4-2 type, weighing 42 tons in work trim, against the present KB (4-8-4) of 140 tons. The symbol “2-4-2" represents the wheel arrangement of the locomotive, and is the method generally employed in identifying the various types of engines. The original K’s . were brought into service on the opening of the through line from Christchurch to .Dunedin,. and it is of interest to: note that they were the first “2-4-2” oh “Columbia” type to be constructed in the world. It is a coincidence that the tractive effort of the original K was approximately the same as that which will be developed by the "booster” in the new KB engine.