Brake Tests

100 sufficiently objectionable to be prohibitive. The action was such that the result would have been better had the.braking power on the UC equipment cars been 125 per cent, instead of 150 per cent. Emergency Stop at 30 M.P.H. 214. High braking power on the locomotive and mixed equipment on cars as follows:— Car Nos .........1 2 3 4 5 6 7 8 9 10 11 12 Equipment PM PM PM PM PM PM UC UC UC UC UC UC 215. This test was planned to bring out the effect of the worst combination of UC and PM equipments that could be thought of and at a speed which was considered the most critical for such a test. The first time that such a make-up of train was tried out, test 667, consider- able shock was experienced just after the brake was applied and a very heavy running out of slack was created when the train was almost stopped, causing the tender coupling yoke to part. After coming to a standstill the gap between the rear of the tender and the head end of the first car was only about twenty feet. An inspection showed that the fracture was occasioned by defective material in the coupler yoke. This was confirmed by the fact that after putting in a new yoke and repeating the test (test No. 675, Fig. 61), the train did not part although there was a very heavy running out of slack toward the end of the stop. SERVICE APPLICATION STATION STOPS. Two-application Stops, 45 M.P.H., UC PNEUMATIC EQUIPMENT WITH Graduated Release Caps in Graduated Release Position. 216. This test was made with the graduated release caps set to give graduated release on all cars. It was desired to determine what results would follow should the engineman manipulate the brakes according to his usual practice when making a two-application station stop witli the PM equipment, instead of as a graduated release brake equipment is intended to be used. , 217. From the brake cylinder cards (Fig. 62), it will be seen that the brakes applied and released uniformly but, on the release preceding the second application, (this, it should be noted, was equivalent to a graduated release of the brakes,) the brakes did not wholly release. On the second application all the brakes reapplied. 218. It will be noted that the brake on car seven released to a much lower pressure than the other cars in the train before the second applica- tion was made. This is because the graduated release feature on this car was inoperative, due to a faulty condition of the valve as explained in paragraph 222.