TRAMWAYS FOR MAIN SOUTH ROAD

Taranaki Daily News, Volume LIV, Issue 208, 1 March 1912, Page 6

TRAMWAYS FOR MAIN SOUTH ROAD

To the Editor. Sir,—Since reading the article on "A .Coming Question," the electrification of the Main South road, which was published recently in the "Daily News," I have, probably like a good many more concentrated my thoughts on that question particularly as I am interested in electric engineering matters. I would, with your permission, like to dwell on the electrical aspects of the question. On roads, tramways and railways the future lies with electricity—wholly on railways and tramways, perhaps not wholly on roads, but at the root of electric traction there lies the firm faith in its, superior economies and flexibility. Some of the aspects of electric traction are highly technical; others are purely financial. It is impossible to understand the achievements and possibilities of electricity in traction without a certain amount of discussion of both these points of view. Tbe leading ideas embodied in electrh traction systems were contributed by engineers who worked in the general field of electrical engineering; men who have added one brick of experience and ingenuity to another until the imposing structure was made visible to the world. Remarks have been made that tramways are an apology for bad roads. That is to say, if road surfaces were perfect there would be no need to lay rails in order to allow vehicles to run easily. Although this view of the case may be no better than a quarter truth, it is justified to the extent that the tramways were, as a matter of fact, the outcome of an attempt to escape from bad road surfaces. And this appears to be the case with the county and the main south road. Cr. D. McAllum has 'Worked out the correct answer to the problem, which is: lay rails instead of road metal. It has also been suggested to harness several watersheds. The idea that a water-fall provides power "for nothing" is one of. those superficial conceptions which make the hardest of fallacies. To "harness" a water-fall requires a heavy, - expenditure of capital on conduits, pipelines, dams and other works. The interest upon that capital is a heavy item, apart from the cost of maintenance and repairs. Waterfalls are situated in mountainous country remote from centres of industry; the water-power station, therefore, has to face the cost Of transmission mains and the loss of energy 'involved in'carrying the power to the place where it is wanted. Further, waterfalls and the adjacent ground belong either to individuals or to the State, and payment is generally exacted for the right to use them. All these items have to be covered in the price charged for current to the public or the railway undertaking. Nature may provide the head of water free, but man has to spend money in utilising it. Anything which is obtained for nothing is generally worth nothing. The whole of the power-pro-ducing plant for a typical electric tramway or light railway system is concen- ] trated at a generating station placed, if; possible, near the centre of the system. From this station, runs a network of • electric mains to feed the lines with: current at convenient joints. This concentration is a benefit on several grounds. A large generating equipment is cheaper in first cost than a multitude of small power-producing plants, and it is much more economical in operation. If every car had its own power equipment, that equipment would need to be powerful enough to haul itself and the loaded car ! up the steepest gradient on the route. That is to say, the sum of the car capacity would be equal to the sum of the maximum demands. But when the power is obtained from a single stationary course we do away with the deadweight equipment on the car, and secure the very vital advantage that the capacity of the stationary source need not be so great as the sum of the maximum | demands. j

There are three systems which might be successfully worked on that routeFirst, hydro-electric; second, oil-gas electric ; third, petrol-electric. The first and second systems are stationary, and involve costly overhead lines and railbending, the prime mover being water, crude oil or petrol. With the petrolelectric system the cars are self-contain-ed, and what one might term a generating station on wheels. This system would be, I have no doubt, the cheapest to instal. There would be a simple and light permanent-way. The only drawback to this system is. as stated abovo, that the car equipment would need to be powerful enough to haul itself and the \ loaded car up the steepest gradient. This system has, I believe, been proposed for suburban traffic in New South Wales. If space allowed, I should like to give | the results of a petrol electric car tested on the road surface with rubber tyres. If the sariie car had been tested with steel wheels running on steel rails surprising results would have happened, as nothing demands a lower tractive effort. The test of this car was taken over an exceedingly hilly route. The average running weight was 7.683 tons, fitted with a 38-h.p. engine, giving a maximum of 42-h.p. at high speed. The trial was night and day, and the speed not allowed to exceed 12 miles per hour, a. factor which no doubt increased the fuel consumption. The route contained a good stretch of 1 in 'lO and 1 in 11 gradient. The length of the gradient was 4062 ft and the total rise was 360 ft. The maximum average speed up the hill was 7.20fi miles per hour. The fuel consumption gave the excellent result of 58 ton-miles to the gallon. The engine was started from the battery about 80 times during the trial; and the electric lighting proved quite reliable, In addition to the engine starting a constant discharge of 8 amperes from the battery was maintain for eight hours out of the 24 for lighting. —I am, etc., W. H. HEWLETT. Mangorei, February 27.