The Future of the “Iron Horse”

To-Day many influences are at work tending to effect vast changes in every field of railway activity. For many years, however, it seems likely that the steam locomotive will continue the principal agency in long-distance passenger and freight movement, and all over the world this faith in the future of the steam engine is reflected in the many new, increasingly powerful steam locomotives being put into service. In Britain, new types of steam locomotives are being constructed to handle the long and heavy trains which to-day are standard practice, and recent locomotive additions on the Great Western and London and North-Eastern lines are of considerable interest.

At the Swindon shops of the Great Western, there are being turned out a batch of eighty, two-cylinder, 4-6-0 type engines, to be known as the “Hall” Class. These are intended for heavy passenger train haulage in and out of the Paddington Terminal, London. The new locomotives have outside cylinders, 18 1/2in. diameter and 30in. stroke. The coupled wheels have a diameter of 6ft., and the bogie wheels of 3ft. The boiler barrel is conical in shape, and a Belpaire firebox is fitted, the working pressure being 225lbs. per sq. in. At 85 per cent. of the boiler pressure, the tractive effort is 27.275lbs. The tender carries 3,500 gallons of water and 6 tons of coal, and is of the familiar six-wheeled pattern. The total weight of locomotive and tender is 115 tons.

On the London and North-Eastern line the latest type of steam locomotive to be constructed takes the form of a batch of 4-6-0 type fast passenger engines, for use on the Great Eastern section of the system. These are three-cylinder machines with a tractive effort of 25,380lbs. The outside cylinders are equipped with Walschaerts valve gear, and the inside cylinder, which drives the leading coupled axle, is equipped with Gresley valve gear. The cylinders are of 17 1/2in. diameter and 26in. stroke, while other dimensions are as follows: Diameter of coupled wheels, 6ft. 8in.; diameter of bogie wheels, 3ft. 2in.; grate area, 27 1/2 sq. ft.; length of boiler barrel, 13 1/2ft.; diameter of boiler barrel, 5 1/2ft.; total heating surface, 2,020 sq. ft.; working pressure, 200lbs. per sq. in.; coal capacity, 4 tons; water capacity, 3,700 gallons; empty weight of engine, 69 3/4 tons; empty weight of tender, 19 tons.

A most interesting subject for conjecture is afforded in the trend of locomotive design in the years which lie ahead. In this connection a helpful paper, worthy of more than passing notice, was recently read before the Institute of Locomotive Engineers, by Dr. D. S. Anderson, Principal of Derby Technical College. Pointing out that, to-day, the problem confronting page 17 railway engineers was the development of a locomotive giving increased power and higher economy, without undue increase in size, weight, or complication, Dr. Anderson stated that solutions were offered by internal combustion, with various forms of drive, and by the steam turbine and condenser, or the steam reciprocator and condenser. The conditions of railway operation were unfavourable to the internal combustion engine, but the steam turbine offered many advantages.

The economy of the turbine, and its ability to develop enormous powers in a comparatively small casing, it was remarked, were well-known. It had the further attraction of purely rotary movement and perfect balance. On the question of drive, it was pointed out that, in order to develop the power in the limitations of space, the turbine would have to run at 6,000 to 10,000 r.p.m., and obviously some kind of speed reduction device was needed. Two solutions had been tried, the electric drive, with generators and motors, and the gear drive. The first could be ruled out from the cost point of view, as well as from the questions of weight and complication. Gear drive was a possible solution and one that had achieved a fair success. Experimental turbines built in Britain, Germany and Sweden, had given decidedly encouraging results, and considerable development along this line was likely.

The possibilities of development in boiler practice lay in increased working pressure, alteration to a water-tube type, and improved methods of firing. The development of higher pressures would, by degrees, force an alteration in design owing to the unsuitability of the existing type to carry very high pressures. There were many arguments in favour of a change from existing design, and any alteration would be in the direction of the water-tube type, the advantages of which were—ability to withstand the highest pressures, more perfect circulation, quicker steaming, ability to deal with fluctuating demands, lighter weight both in material and water quantity carried, and greater elasticity in design.