Brake Tests

103 219. At the end of the stop a surge was experienced as is usual if a high pressure remains in the brake cylinders when the train comes to a standstill. Except for this the stop was smooth, indicating that with the graduated release feature cut in, a two-application stop can be made in the customary manner without the likelihood of undesirable results. Graduated Release Station Stop at 45 MILES PER Hour—UC Pneumatic Equipment. 220. This test was made to illustrate the proper method of making a graduated release stop (Fig. 63). The initial application was made with one continuous full service brake pipe reduction, was then held a few seconds after which the release was graduated by moving the brake valve handle from lap to running position and then back to lap position, four distinct graduations being made. This resulted in the braking power being reduced substantially in accordance with the decrease in the speed of the train. 221. Except for the first three cars in the train, which felt the effects of a graduation of the release most promptly and consequently tend to release sooner than the cars toward the rear, the amount of brake cylinder pressure remaining when the train stopped was uniform throughout the train. 222. The indicator card shows that no graduation of the release was obtained on car seven. It was found on inspection that this was caused by dirt on the seat of one of the valves which condition prevented the emergency reservoir from performing its graduated release function. 223. This stop was very smooth from the beginning of the appli- cation until the train came to a standstill and the low cylinder pressure remaining at the end entirely eliminated the unpleasant surging usually experienced when the train comes to a stop with high pressure in the brake cylinders as was the case in test No. 662. (Fig. 62.) 224. This shows that the brakes can be applied to give a high braking power when the speed is high, which is essential if time is to be saved in making stops and yet the stop made as smoothly as if only a very light retarding force had been applied. Station Stop. 225. Mixed equipment on cars as follows: Car Nos.......1 2 3456 7 8 9 10 11 12 Equipment PM PM PM UC UC UC PM PM PM UC UC UC 226. The stop was made with a full service application followed by a release and then a second application to bring the train to a stand- still, in other words the usual two-application method. The only feature requiring special mention is the behavior of the PM equipment on