This section is from the "Modern Machine Shop Construction, Equipment, And Management" book, by Oscar E. Perrigo. Also see Amazon: Modern Machine Shop Construction, Equipment, And Management.
Figs. 149 and 150 show a dumping car, arranged from one of the regular cars, with the platform omitted. As will be seen, the box or body of the car is not pivoted upon trunnions, but supported upon a cast iron rack, with cast teeth, at each end of the car, this rack being engaged by a toothed segment fixed to the car body as shown. The object of using this toothed device in preference to simple trunnions or pivots is to carry the car body toward the side where the load is to be deposited when the car is dumped. The device is simple and effective. The side supports, A A, are pivoted to the frame of the car and are used to hold the car body in its normal position. The sides of the car body are pivoted at the top, as shown in Fig. 150, and held or released by a simple latch at their lower edge. A small safety chain may be added on each side to prevent the car body from becoming unshipped by careless dumping.
Fig. 149. Side Elevation of Dump Car.
Fig. 150. End Elevation of Dump Car.
These cars may be used in transporting coal, ashes, coke, molding sand, and all similar materials which may be quickly unloaded by dumping. Those used for carrying coal to the boiler room may have a horizontal shelf on a level with the bottom of the car body, and on the side toward the boilers.
However, a more convenient arrangement will be a solid box of three sides, or two ends and a side, built upon an ordinary platform car, the side toward the boilers being pivoted at the bottom instead of at the top, as shown. This will be convenient to shovel coal from. But the dumping car, as shown, should be used for the removal of ashes. For either coal or ashes the car bodies should be lined with sheet iron.
Fig. 151 shows a large car formed by placing upon two ordinary flat cars a platform constructed of 2-inch planks, running lengthwise, and held together by cross bars 2$ inches thick, and a similar bar running lengthwise on each side of the platform, and within two inches of its edge. Such a platform may be from 34 to 42 inches wide, and from 7 to 10 feet in length, according to what use it is intended for. Cross bars at least 12 inches wide should be built with the platform, at the points over the centers of the cars, and through these is placed a "king bolt" as shown, which furnishes a pivot upon which the separate cars turn, the same as the trucks of a railroad car. It will be readily seen that such a car will carry double the weight of the ordinary platform car as the weight is distributed upon eight wheels instead of four. Cars for use in the yards may be heavier and longer than those used in the shops if the conditions demand such increase. For instance, the cars may be made 38 inches wide and 6 feet long instead of 34 inches by 5 feet.
Fig. 151. Double Car. Two Cars and a Special Platform.
The frames should then be of 3 x 8 inch instead of 2 « × 7 inch timbers. The wheel base should remain the same, in order to facilitate the passage of the car around the curves.
As to the number of cars necessary for the equipment of the entire plant, much will depend, of course, upon the particular character of the work to be done, but in a general way it may be stated somewhat as follows: Of the ordinary flat cars, as shown in Figs. 141, 142, and 143, there will he needed 16 cars, distributed among the different departments. Of these, 6 at least should have stake pockets and a sufficient number of stakes provided for them to give ten stakes to a car. There should also be 10 of the removable boxes shown in Fig. 146 for use on them if needed. There should be 6 dump cars for use in the yard, foundry, and boiler house. The special cars shown in Figs. 147 and 148, and such modifications of them as may be necessary, will be used mostly in the machine shop galleries, and their number will be determined to a very large extent by the kind of work that is to be done. There should be at least two of the platforms shown in Fig. 151, to be used on any of the flat cars. The number of cars above mentioned is considered really essential to the proper handling of the usual classes of stock and material, but a larger equipment will doubtless be advisable whenever the first cost is not closely limited, as a lack of proper transportation facilities, while there may be a saving in first cost, will prove a matter of continual expense in not being able to handle stock and material to advantage, and with the economy of labor cost that a complete equipment would permit to be done with ease.