Brake Tests

128 Comparing the braking powers for the train using the No. 1 clasp, the standard, and the No. 2 clasp brake and for the twelve car break- away stops with these types of rigging it will be seen that the variation is not sufficient to materially affect the average results obtained. 283. The greater difference in the per cent, of braking power which is' shown between the No. 2 and No. 3 clasp brake riggings must be taken into consideration when comparing the stops made with these two types of brake rigging. A full explanation of this condition and its proper interpretation in making a comparison of the stops of these two cars will be found in Par. 400, but it should be noted here that a comparison of the stops with the No. 2 and No. 3 designs of clasp brake cannot be made on the basis of the figures given in the table but should be made in accordance with the explanation given in that paragraph. 284 With the above circumstances in mind it can be stated that the stops with the standard brake train were on the whole longer than those with the No. 1 design of clasp brake. This statement is based largely upon the consistently better showing of the No. 1 clasp brake in the breakaway stops, which better showing is more than can be ac- counted for by the 5 per cent, higher average braking power. Further- more, the breakaway stops with the standard brake train while un- doubtedly longer on account of the poor shoe con ition on is ram during these stops, were on this very account more nearly represen- tative of the characteristic condition of this type of rigging than the train stops, especially the shortest (1049-feet stop) which was obtained 1 • Lu F when the shoe condition was better than the early in the series of runs when the soc average for this form of brake rigging. 285. The stops with the No. 2 clasp brake were uniformly shorter than with the No. 1 clasp brake, although the average percentage of in favor of the No. 1 clasp brake through- braking power was slightly in favor oi that the difference out. It should be noted in this connection, however, that the difference , , • the cases referred to is due to the in the per cent, braking power in the c 1:1 inherent action of the rigging as affecting the cyhnder pressure obtained because in this case the per cent, braking power per pound of brake 1* icallv the same. This means that the difference in the average per cent braking Power - due to the action of the equipment itself, 286. The No. 3 design of clasp brake was tried on a single car only. Consequently its performance has to be compared with that of the No. 2 clasp brake on a single car. The braking Power per pound of brake cylinder pressure for the No. 3 clasp brake was higher than that of the car having the No. 2 clasp brake as shown in the table and due allowance must be made for this, as explained in Par. 400, Fig. 115,