The Mechanical Handling and Storing of Material

SELF-EMPTYING RAILWAY WAGONS 497 the old-fashioned wooden trucks, and one of the pressed steel unloaders, but both having a capacity of 1,500 tons, it is evident that in the former case thirty trucks of a total weight of 750 tons would be necessary, whilst in the latter case only fifteen wagons of a total weight of 462 tons would be required, which means that a saving of 288 tons dead weight is thereby effected. The trucks are so constructed that the hoppers are only raised a few inches above the flaps of the shoots on the unloading staiths. Hence, when the sliding doors are removed, the coal falls on the shoots with but little force, and thus the breakage between the wagon and the shoot leading into the ship’s hold is reduced to a minimum. Self-Emptying Wagons of the North-Eastern Railway.—These are built by Messrs Sheffield & Twinberrow, and are for loads of 35 tons, the tare being 14 tons, or 40 per cent, of the paying load, as against 50 per cent., which is about the average of 10-ton wagons. Self-Unloaders of the Baden State Railway.—These are built on the Nossian system, in which the body of the car is moved by rack and pinion to one side for unloading purposes. They are, however, slightly hoppered on both sides, and therefore empty entirely, whereas the Nossian require the last of the load to be moved by hand. Figs. 699 and 700. Self-Unloader for Liquids. One of these trucks is illustrated in Figs. 688 to 691. It will be readily understood that the body of the truck need not be moved so far to one side as in the Nossian system. This truck has a capacity of 18 tons. The under frame is generally of iron construction, whilst the upper portion is usually of wood. Self-Unloader of the London and North-Western Railway. — This self- unloader may be seen in Figs. 692 to 694, which show one of these trucks in plan and two elevations. It is built principally of wood, is hoppered, and discharges its load from two large outlets at the bottom of the truck, the discharge being effected by withdrawing a pin which releases the doors. Each outlet is really again divided into two halves, and in the cross section one half of the outlet is shown open. All the other parts of the wagon are clearly seen in the illustration, and require no further description. Ballast Wagons of the Great-Western Railway.—A wagon of this type is shown in Figs. 695 to 698. These ballast trucks, though self-unloading, have not been built expressly for the conveyance of coal or minerals. They were designed for the purpose of depositing ballast on the permanent way. The operation of laying and spreading is effected as the train moves slowly forward, but there is no reason why wagons of this type should not also be used for the delivery of coal or minerals. The 32