The Locomotive Of Today

The Framing, Wheels, etc. : Sandzng Gear 151 across between the sand boxes, under the boiler, and operating both sand valves simultaneously. At B an enlarged section and plan of the outlet valve is shown. The valve of cast iron has a pin upon it below, fitting in a hole in the sand box, and a square above, upon which a Socket on the spindle is placed; this spindle passes up through a guide nut, and carries a crank above for actuating it. The sand is well dried by being baked in a kiln and sifted through a screen, the mesh of which is less than the hole in the sand box through which it must pass to the sand pipes. When there is a strong side wind, or when the engine is running round a sharp curve, it often happens that the sand from pipes as shown at A fails clear of the rails; or if the engine slips and cannot be moved at all, the sand will not g'o under the wheel, and the fireman must get down and push it under with his shovel. To overcome these difficulties it is now usual to fit up a steam sanding gear, so that the sand may be driven under the wheel to the point of contact with the rail. Messrs. Gresham & Craven’s steam sander is shown at C as fitted to the front of a large wheel. The sand box forms a frame stay between the inner and outer frames, and is carried down below them. To the bottom of it the “ sand trap ” is fixed; from this a pipe leads down to the sand “ ejector/’ to which steam is also led, and carries the sand through a pipe directly under the wheel. D gives an enlarged section of the trap. The sand enters above and filis the pocket, but is prevented from passing out by the lip projecting up above the level of that reaching down. When, however, steam is admitted to the ejector below, a partial vacuum is formed in the pipe, and air rushing up the beil mouth carries sand over the ledge with it down the pipe to the ejector. E is a section of the ejector: steam enters through a small pipe and issues from the nozzle, inducing a stream of sand as clescribed. Any moisture that may be formed in the steam pipe can escape out of the small hole at the bottom of the ejector. The steam valve on the boiler for operating this apparatus is specially arranged to prevent any leakage passing to the ejectors when not in use, and the pipes from it must not have any “ pockets ” to retain condensed water in, but must be led as straight down as possible, and the “tee” connecting the two ejectors, one on either side of the engine, must be placed as nearly midway between them as practicable, so that the quantity of sand delivered will be equal on each side. Compressed air is also used for driving sand under the wheels, and sometimes the discharge from the drivers valve