RAILWAY ENGINES

Evening Post, Volume CII, Issue 17, 22 July 1921, Page 11

RAILWAY ENGINES

LITTLE ROOM FOR IMPROVEMENT

POWDERED COAL AS FUEL.

According to Sir. S. H. Jonkinson, who read a pa.per on the development of locomotives in New Zealand at a meeting of the Philosophical Society (Technological section) this week, there is very little room for improvement in railway engine design in this country. He made it plain that the statement referred not to engines in actual use, but to new ones, because, as many old locomotives were necessarily in service, practice necessarily lagged far behind design. The conclusion of the argument was that, 1 so high is the efficiency of the modern locomotive as a heatusing machine, the only direction in which advance can be sought at present, is in ths use of a new fuel. Oil, Mr. Jenkinaon ruled out gn the score of its high cost, and he suggested that the greatest probable improvement lay in the use of powdered coal. This would not give any greater efficiency, but it would be cheaper than ordinary coal and would abolish the smoke and dirt which were the cause of distress to .passengers and locomotive engineers alike.' The lecturer also made comparisons between electricity and steam for railway service in this country. His remarks on this subject, as well as on certain other aspects of railway design, have been reported under separate headings. The audience, consisting mainly of men closely interested in engineering, were much interested .in the lecturer's remarks on the efficiency of tile locomotive. He rated the operation of the boiler at the very high figure of 95 per cent.—an estimate which some of the listeners were inclined to dispute. The very fine performance of the locomotive boiler was due to the forced draught, which gave complete combustion with a minimum of air. The engine itself, Mr. Jenkinson said, was a much better machine than was usually supposed; and in first cost was probably the cheapest power plant in existence for powers of 150 horsepower and over. A locomotive could be built for about £8 per horsepower, as against £30 or so for steam turbines, and £60 to £80 for waterpower, installations. He gave data obtained from trials of the "Ab" type of locomotives to show that these engines developed easily 1000 horse-power, with a coal consumption'of two' pounds per brake horse-power per hour. He doubted if better performances were made anywhere except when special firing was adopted simply to produce remarkable figures. In ordinary miming .over a week, on the Tiruaru-ChristcTiurch line, th»> total coa! consumption was found to be 3 pounds per horse-power, including the coal burnt while the engine, was not drawing the train. On less favourable lines, such as between Wellington and Taihape, the consumption was'about 4 pounds of coal; and on the Rimutaka incline the old-fushioned engines in use worked on 8 pounds of coal per'horse-power-hour. '

These . high efficiencies obtained were,' Mr. Jenkihsori said, typical of modern engines using super-heated steam, and they could not expect to see them much" improved on.' There had been tentative but unsuccessful experiments with, turbine - locomotives, not to be taken vftry seriously at present. Ho did not vcgarcl oil as a suitable fuel for railway purposes. Oil engines were not likeJy to work well, because they must work at fixed speed to give efficient results. Oil fuel, moreover, was, in his opinion, certain to remain, deare? than coal because of tlio demand for fuel for motorvehicles and aircraft, which could not use coal. Oil need not be considered as a railway fuel, especially, ag electricity could <lo everything that oil could, and something ifc could not.

Powdered coal,. Mr. Jenldnson said, was without doubt a very .promising fuel for railway purposes. The Jtaihtay Department had lately Been making experiments with excellent results. The New Zealand coal mines produced slack not as a by-product, but as their main output; and this could be bought very cheaply, an<l turned into powder at a much lower cost than tlie price of ordinary coal. Pumped into a fire-box with air-pi'essure, powdered coal was an ideal fuel' There was no noticeable economy of consumption o.vor lump Coal, but the powdered coal was burnt absolutely without- smoke and without sparks. The resulting cleanliness was highly, important, for nothing was more annoying to the locomotive engineer than the dirt caused by the use of bituminous coal.. It caused more trouble than anything else. Powdered coal would cut the fuel biil to,, about half its present size. In that; so far as he could see, lay the only improvement possible in the steam locomotive.