Brake Tests

123 from the brake cylinder to the brake shoe, so as to provide as nearly as possible an instantaneous transmission of force with minimum loss. Clasp Brake No. 1. 271. The clasp brake rigging No. 1 is shown in Figs. 3, 7 and 69. The dead lever of this rigging was anchored to a bracket on the center sill of the car and over the center of the truck bolster, but at a slightly greater height above the rail than the top of the dead lever to which it was connected. During the brake applications the dead lever tended to rise to the same height as the bracket on the center sill. This move- ment was limited by the compression rods striking the guides in which they moved, thus causing a binding of the rigging at this point. This binding was eliminated by removing the guides. In this design of truck rigging the turn buckle rods pass below the axles to the outside shoes. This requires special provision to insure against these rods dropping on the track and requires that they be disconnected when changing wheels. 272. The total shoe pressure on the wheel was proportioned be- tween the inside and outside shoes in the ratio of 60 arid 40 per cent, respectively. Owing to the greater inclination of the inside brake shoe hangers, the inside shoe fell away so far before the angles of the hangers equalized that there was no shoe clearance for the outside shoes, no more slack being available when the piston travel was adjusted to 63 inches for standing service. This insufficient clearance of the outside shoes and excessive clearance of the inside ones, together with faulty lever angles and displacement of members under brake application, resulted in a low over-all efficiency of this rigging. Clasp Brake No. 2. 273. This design of brake is shown in Figs. 5, 7 and 70. The lever angles peculiar to clasp brake No. 1 were eliminated in this design of brake. Considerable displacement of the brake rigging re- sulted, however, from the use of a compression member between the two live truck levers and from the bottom connections to the brake beams being staggered in order to allow these connections to pass. As a result of this twisting of the rigging, several lever pins were worn off due to their rubbing the wheel. This condition was remedied by the addition of a box section on the bottom connections, which allowed them to pass in the same vertical plane without interference during brake application. These bottom connections were placed below the axles and introduced an undesirable feature as pointed out in Par. 310. 274. The vertical spacing between the top of the dead lever and the anchor to which it was connected, resulted in a tendency of the rigging to lift until the pull between the members took place in a horizontal plane.