The Mechanical Handling and Storing of Material

THE COALING OF RAILWAY ENGINES 627 The conveyor is of the well-known Babcock-Wilcox “tipping tray” type, running at a speed of 70 ft. per minute afid capable of lifting about 60 tons per hour. Adjustment is provided for at the bottom end, while the driving gear is situated at the top under the bunker housing, and consists of a 660-volt direct current electric motor of 9 H.P., driving through a belt and train of machine-cut gear wheels, the effect of which is to give a very quiet drive. All coal is delivered over the end of the conveyor track, but in order to prevent any breakage at this point a special form of balance plate retains it on the trays until the lowest point of the terminal pulley is reached, when it has a fall of only about 1 ft. on to the inclined shoot which delivers it to the requisite division of the bunker. In approaching the design of the bunkers it was necessary to weigh carefully the relative advantages of the large bunker against those of the small bunker, and in this case the balance was on the side of the former. The bunkers were therefore designed to hold 300 tons; this is more than enough to coal all engines during the night without the conveyor working, and it is thus possible to send up during the hours of daylight all the coal required, and to save double-manning the wagon tippler and conveyor. Owing to a large number of main line engines being loaded with two classes of coal, namely, Welsh and “hard,” it was necessary to provide separate storage for each dass. The bunker is accordingly divided into two main parts, to store 100 tons of Welsh and 200 tons of “ hard ” coal. Working on the large bunker principle necessitates special arrangements to break the fall from the delivery shoot to the bottom of the bunker, when the latter is fairly empty in the mornings. This is done by special baffle plates in the case of the “ hard ” coal, and by spiral shoots in the case of the Welsh coal. The coal is thus delivered with a minimum of breakage, even when the bunkers are completely empty. There is an outlet on each side of each division of the bunker, or four outlets in all, so that tenders can be coaled on both sides at the same time. The outlets in ■question measure 2 ft. by 2 ft., and are provided with undercut balanced doors, worked by hand, which up to the present have been very successful and free from “jams.” By ■opening one of the doors coal is permitted to flow into a calibrating chamber formed in the shoot between bunker and tender. The bottom end of this chamber is closed by a. door, worked by a lever conveniently situated, and it is so arranged that the contents of the calibrating chamber are equal to 10 cwt. On the upper door being shut and the lower door being opened, the 10 cwt. of coal is free to slide on to the tender. The shoots are built at an angle of 45° to the rail. The lower doors have adjustable hinges, which allows the capacity of the calibrating chamber to be varied until the best average is arrived at. It has been found possible to set these bottom doors so exactly that the difference between the calculated weight delivered to the tenders and the known weight sent up to the bunkers was only 4 tons 1 cwt. in a month’s working, or about 1 ton per calibrating chamber per month. This method of obtaining the weight has therefore proved quite satisfactory; so also has the speed of coaling—as much as 6 tons being put on in three minutes, as against 5 tons in fifteen minutes with the old system under the most favourable circumstances. The average daily quantity of coal placed on tenders is now about 450 tons, and the new plant performs this task with a staff of three men by day and one by night, the -conveyor being at work approximately ten hours per day.