The Mechanical Handling and Storing of Material

656 THE MECHANICAL HANDLING OF MATERIAL Dock No. 1, and in 1910 an addition was made which increased the storage capacity of this plant to 265,000 tons. The capacity of the plants erected under the “ Dodge ” system aggregates a total of about 5.000,000 tons. While official figures are not obtainable for publication, it is guaranteed that the labour cost of either stocking or reclaiming on an active plant will not exceed four cents (say 2d.) per ton. Coal Store of the Philadelphia and Reading Railways at Richmond Harbour, Philadelphia, United States of America.—This is probably one of the largest coal stores in the world, the harbour of Philadelphia being the centre of the very extensive coal traffic of the Reading Company, who own not only the collieries, but also harbours, railways, and ships. The coal arrives from the collieries in complete coal trains, the contents of which are, if possible, discharged direct into the ship, being drawn up inclines on to staiths where the trucks discharge through bottom doors and by gravity shoots into the vessels. It is, as a rule, impossible to entirely dispose of the coal thus, so it is piled up in a stock heap which will hold 180,000 tons. The store consists of six cone-shaped piles (on the “Dodge” system), two of which will hold 40,000 tons, two 30,000 tons, and two 20,000 tons. Two parabolical bridge girders are erected to form an angle with each other, slightly larger than the angle of repose of the coal; these girders are held in position by guy ropes. The coal is discharged by bottom door wagons into a hopper between the rails from which it is conveyed up one of Figs. 920 and 921. Stock Heap of the New York Central Railway at Dewitt. the girders by a push-plate conveyor. The withdrawal of the coal from the heap is effected in a manner similar to that employed in the installation previously illustrated and described. The cost of stacking the coal varies with its size, from one halfpenny to one penny per ton for coal 1| in. cube to 8 in. cube, and one farthing to a maximum of twopence halfpenny for the removal of the respective sizes. This difference in cost is accounted for by the fact that the small coal will run on its own account into the conveyor whilst the large coal requires some assistance. Stock Heap of the New York Central Railway at Dewitt.—This is illustrated in Figs. 920 and 921. Through the centre of the pile four lines of rails are laid, of which, however, only the two outer ones proceed straight through ; these sidings are for the accommodation of the hoppered bottom wagons which bring the coat. As may be seen from the cross section there is a V-sbaped trench, into which the wagons discharge, and the coal is then taken by grab and transferred on to the pile. The bridge crane can traverse the whole circle for distributing the coal, working from one