The Mechanical Handling and Storing of Material

UNLOADING OF RAILWAY WAGONS (Continued) CHAPTER XXXV UNLOADING RAILWAY WAGONS BY MEANS OF TIPS OR HOISTS The method of unloading railway trucks described in this and the preceding chapter is without doubt one of, if not the most, rational means of handling material, because the operation itself is the simplest and quickest, and by its means the greatest quantity can be handled in the shortest space of time, provided the mechanical appliances which give life to the method are economical and up to date. The appliances, which are hereafter described, are classed under three headings. Each of these three different types of tips is suitable for a different purpose, mainly depending upon local conditions, such as the height of the railway siding or quay above the water level in the port, river, or other destination of the material to be unloaded. The three types of tips are the following A. Tips which unload below the level of the railway lines, also called Gravity Tips. B. Tips which unload on the same level as the railway lines. C. Tips which unload above the level of the railway lines, generally called Coal Hoists. The type B is more particularly used for unloading coal, etc., from trucks in factory yards, whilst types A and C are generally used for loading ships with minerals and cargo or bunker coal. A—Tips which Unload Below the Level of the Railway Lines.—It is obvious that the operation of unloading trucks for the purpose of depositing the contents below the rails can be performed without the expenditure of power, as the weight of the coal itself is sufficient to tip the truck, and to use the inertia either directly or after being stored in accumulators to right the truck after emptying. Tips of this type are most economical when the rails on which the trucks arrive at the tip are high above the point where the coal is to be received. This condition obtains but rarely in factory yards, but is frequently met with on the banks of tidal rivers. In such cases these tips are ideal appliances, as no driving power is required, and the material is conveyed to its destination (generally ships) by gravity. The truck when tipped is in such a position that the front edge of the platform is 6 to 8 ft. below the level of the rails, so that if the rails are not above the ground level an excavation of 20 to 30 ft. below the rails may be necessary, in order to receive and further dispose of the material by other mechanical means (see Fig. 730). Such exca- vations add so much to the capital expense, that tips of this type are rarely economical unless, as stated above, the rails are well above the ground level. The following are a number of examples of coal tips of this class :— The Old Newcastle and Cardiff Tips.—The old Newcastle and Cardiff tips are 5T5