A. Close the cut-out c.o.c.k in the main reservoir supply pipe, this to avoid the waste of air when a brake application is made on the train.

187. Q. If the brake pipe connection to the control valve breaks, what should be done?

A. Plug the end leading from the brake pipe; the automatic brake cannot be applied on the locomotive, but the independent brake will not be affected.

188. Q. If the control cylinder pipe breaks, what effect will it have and what must be done?

A. The locomotive brake cannot be applied with the automatic brake valve; by plugging the pipe, this feature of the brake will be restored, but the independent release feature will be lost.

189. Q. If any of the pipes here enumerated breaks, will it in any way affect an application of the independent brake?

A. No; as the independent and automatic features are entirely separate from each other; that is, the automatic control valve is not brought into use when an independent application of the brake is made.

CONTROL VALVE DEFECTS

190. Q. If there is a blow at the control valve exhaust port when the brake is released, where would you look for the trouble?

A. This would indicate a leaky application valve, or a leak past the emergency valve.

191. Q. If there be a continuous blow at the control valve exhaust port when the brake is applied, where would you look for the trouble?

A. This would indicate leakage past the exhaust valve 7.

192. Q. If the locomotive brake released with the automatic brake valve in lap position, where is the trouble?

A. Would look for a leak in the control reservoir pipe or special release valve.

193. Q. If the brake remained applied in lap position, but released in release or holding position, where would you look for the trouble?

A. This would indicate a leak in the control valve release pipe.

MISCELLANEOUS

194. Q. What is meant by an application of the brake?

A. The first and all following reductions, until the brake is released.

195. Q. How many applications of the brake should be made when making a stop with a pa.s.senger train, and why?

A. Two; the first a heavy one to reduce the speed quickly, and the second a light one to complete the stop; thereby preventing wheel sliding and shock to the train.

196. Q. How many applications of the brake should be made when making a stop with a long freight train?

A. One; this to prevent the possibility of causing damage to the train.

197. Q. Explain how a stop should be made with a freight train.

A. Probably no more difficult question to answer could be asked, as the service braking of a train must be governed by the condition surrounding it; meaning, relation of brake power to weight of train; rail condition; speed and grade. To prevent breaking in two and other damage, freight trains should be stopped with one brake application, which may consist of one or more reductions, up to full service. Generally speaking, the slack should be bunched before the brakes are applied, and this may best be done by gradually closing the throttle and allow the train to drift some little distance. The first reduction should not be less than five or more than eight pounds. The brakes should be applied as soon as possible after the slack has had time to run in, the object of this being to have the train slack adjusted while the brakes are least effective, due to the high speed and light brake cylinder pressure. It is at this time that damage may be done to the train; therefore, if the slack be kept bunched or stretched, as the case may be, the possibility of train damage will be greatly reduced. To obtain this condition, complete the stop with as light a brake application as permissible. When the brake is first applied, the engineer should note if the tendency be for the train slack to bunch or stretch, and having learned that the train is inclined to stretch badly, he can keep the slack stretched by making the initial brake pipe reduction before shutting off steam, then shut off steam gradually as soon as the brake valve exhaust port closes, the object in working steam being to prevent the slack running in as the application is made, which in turn will prevent severe jerks due to the slack running out as the rear brakes become effective. Where the locomotive is equipped with an independent release feature, its brakes should be kept released while the train brakes are being applied.

198. Q. Is it considered good practice to attempt making an accurate stop with a freight train?

A. It may be said to be very poor judgment to attempt making an accurate stop with a freight train, such as a spot stop for coal or water or a close-up stop for a switch. Some engineers seem to think that it is a reflection on their judgment if an accurate stop is not made, but this is not so, due to the fact that no two trains brake alike, and the same train may not brake twice alike. Therefore, aim for a smooth stop, which means a safe stop, leaving accuracy out of the question until the time comes when you are handling a pa.s.senger train.

199. Q. What precaution should be taken after a stop is made on a heavy grade?

A. The air brakes should be released and a sufficient number of hand brakes applied to hold the train. Never rely on the air brake to hold the train for any length of time.

200. Q. Why is it dangerous to repeatedly apply and release the brakes without giving time for the auxiliaries to fully recharge?

A. As time is required to charge the auxiliaries, the feed groove in the triple valve being small, if the brakes are repeatedly applied and released without giving time to recharge, the braking power will be lost.

201. Q. What benefits are derived from the use of the retaining valve?

A. By use of the retaining valve the brake is held applied while the triple valve is in release position and the auxiliary is being recharged; thereby a.s.sisting in r.e.t.a.r.ding the movement of the train down grade, also keeps the train bunched and gives a higher brake power on the second application with the same reduction of brake pipe pressure.

202. Q. With a seventy-pound brake pipe pressure how much of a reduction is necessary to set the brakes in full, and why?

A. About twenty pounds. This will cause the auxiliary reservoir and brake cylinder pressures to equalize.

203. Q. What effect has piston travel on the pressure developed in the brake cylinder?

A. The longer the piston travel the greater the volume or s.p.a.ce to be filled with air; therefore the lower the pressure.

204. Q. When should brakes be tested?

A. Brakes should be tested before leaving a terminal and after any change in the make-up of the train, at all designated points, also, whenever the engineer is in doubt as to his having the control of all brakes.

205. Q. How should a terminal test of the brakes be made?

A. After the pressure is pumped up, a reduction of about ten pounds should be made and the length and force of the brake pipe exhaust should be noted, also the manner in which the exhaust closes; then a further reduction of ten pounds should be made and the brake held applied until signaled to release.

206. Q. If, when making a service application of the brake, the brake pipe exhaust closes suddenly and then begins to blow again, what does it indicate?

A. That the brakes, or at least part of them, have applied in quick action.

207. Q. What is meant by a running test, and when should this test be made?

A. A running test is made while the train is in motion, and steam is being used, when a sufficient reduction should be made to apply all brakes. After noting the efficiency of the brakes they should be released. Running tests should be made following all standing tests and at all other points on the road as required by the rules.

208. Q. When double-heading, which engineman should have full control of the brakes?