The Locomotive Of Today

152 The Framing, Wheels, etc. : Sanding Gear, Buffers. of the Westinghouse brake is carried up to the sand box to sand the rails when the brakes are applied. In Europe it is customary to place the sand boxes upon or below the level of the footplate, but in America they are almost universally placed upon the top of the boiler to give the sand a good fail; and this is made use of in some cases by causing the down pipes to have a “pocket” in them, or a slight rise in some part of their length. The sand is then retained in the boxes without valves, as it will not rise owing to the friction. Com- pressed air is admitted to the top of the sand box to overcome this and Control the supply. Different designers sand different wheels. In some six coupled engines the leading coupled wheels are sanded, in others the driving wheels only, the object being in this latter case to save the coupling rods from the great strain which must inevitably be thrown upon them when the sand gives the necessary grip between the wheels and rails. As little sand as possible should be used, as sanded rails offer more resistance to the passage of the wheels of the train than clean ones do ; and, further, sand should nevet be applied to the rails when the engine is slipping and the regulator open, as the sudden shock due to the stoppage of the wheels when the friction between the wheels and rails is inereased is liable to cause a rupture of the working mechanism of the engine, bent coupling rods, broken crank pins, and even broken crank axles having been caused by this bad practice. The regulator should be closed and the slipping stopped before sand is applied, and then the reg'ulator opened gradually, so that the power will be steadily developed to avoid jerks and snatches. The buffers with which all engines on the standard gauge railways of this country are provided next claim our attention. They are attached to the buffer beam with their centres about 3-ft. 5-in. above the level of the rails and 5-ft. 8-in. apart, centre to centre, to meet those of the carriages and wagons forming the train. At F, a section through a common form of buffer is given. It consists of a hollow piunger fitting easily in a casing which has a bottom plate rivetted to it; this has a hole through which a centre pin passes. Within the piunger is a block of hard wood and a coiled Steel spring; tlie centre pin passes through a countersunk hole in the head, and after the whole has received an initial com- pression it is secured by a cotter behinel the back plate. This form of buffer requires a hole in the buffer beam to permit the centre pin to travel when the piunger is driven home.