The Locomotive Of Today

144 The Framing, Wheels, etc. : Bogies. springs. The ends of the springs are connected by suitable hangers to the cradles, so that as the engine is running the weight carried upon each axle box is equalised. A is a longitudinal section of the bogie, with tne slide and rubber pad shown at the centre, and the axle boxes, etc., at each end. B is a plan, the lower half in elevation showmg . the cradle which is built up of two plates, the ends ot which are filled in with a suitable block for bearing upon the axle boxes, whilst the centre portion is swelled out to clear the spring buckle ; hangers are provided with pins at the required distance from the centre. The top left hånd box is in section, and the top rig-ht hånd box in elevation showing the shape of the projections upon which the hollows in the cradle ends rest on the top ot the boxes. C is a half transverse section through the centre of the bogie, D is a half transverse section through the axle box. etc., and E a half end elevation, showing the distance niece and stav between the frame plates of the bogie. Bodies are often made with the frames much nearer to^ether than that illustrated, with the springs, cradles, etc., outside them; the rubbers being dispensed with and the centre made metal to metal, with the side play controlling springs of plate or coiled Steel springs. Also, mstead ot the cross slide travelling in a straight line the guides are some- times made curved to a radius, but it is very doubtful 11 there is any corresponding advantage to compensate for the extra cost of making these radial guides. __ . ' In running, when an engine fitted with this bogie takes a curve, the frame partially revolves rouncl the centre pin, and the slide moves over towards the side the curve leads, com- pressing the rubbers on one side, whilst those upon tne otlier side assist the engine in smoothly following the bogie; on regaining the straight road, the rubbers return the frame to the centre line of the engine and retain it steadily there. The weight carried upon the whole bogie usually corres- ponds to that carried upon the next pair of drivers, so that the load upon any one part of the rails is half that upon t ie drivers when the bogie leads, the rails being thus gradually forced down to a bed, ready for taking the heavy weight that follows. . , The Stirling bogie has a different side controlling gear. The bogie frame stay is of hollow form with a pivot behind the transverse centre line, and on the longitudinal axis oi the boffie ; the bogie centre pin moves freely in a slot in the frame stay. On the opposite side of the bogie centre to the pivot are two sockets standing out at an angle to the centre pin, thus forming a Y with the bogie centre at the fork; the pivot