75.  Q. If a final discharge valve breaks, what effect will it have on the compressor?

A. Will cause the compressor to stop when the main reservoir pressure is in excess of forty pounds.

76.  Q. How would you test for a defective final discharge valve?

A. To test for this defect, bleed the main reservoir pressure below forty pounds, and if the compressor starts it indicates a defective discharge valve.

77.  Q. If a final discharge valve breaks, what may be done?

A. As the receiving valves and final discharge valves are the same size, the defective valve may be replaced by one of the receiving valves, blocking the opening made by the removal of the receiving valve.

78.  Q. Where piston rod packing is blowing bad, what may be done to stop it?

A. This generally indicates lack of lubrication, and by cleaning and oiling the swab the trouble may be overcome.  However, there are times when leakage by the packing is so great that the oil is blown off the swab as fast as it is applied, therefore is of no value in lubricating the parts.  Where this condition exists, a little hard grease wrapped up in an old flag and tied around the piston rod will ensure its being lubricated.

79.  Q. If the compressor stops, how can you tell if the governor is responsible for the trouble?

A. By opening the drain cock in the steam passage between the governor and the compressor; if steam flows freely, the trouble is in the compressor; if not, it is in the governor.

80.  Q. How may a compressor often be started when it stops?

A. By closing the steam throttle for a few seconds, then opening it quickly; if this does not start it, try tapping the main valve chamber.  This will usually overcome the trouble where the compressor stops on account of lack of lubrication.

81.  Q. What will cause a compressor to short-stroke or dance?

A. Too much oil in the steam end; bent reversing rod; or low steam pressure, as when the governor has almost shut off the steam.

ENGINEER’S BRAKE VALVE

82.  Q. Name the different positions of the G-6 and H-6 brake valves.

A. Release, running, lap, service, and emergency position, with the G-6; release, running, holding, lap, service, and emergency positions, with the H-6.

83.  Q. What is the purpose of release position?

A. To provide a large and direct opening from the main reservoir to the brake pipe, for the free flow of air, when charging and recharging the brakes.

84.  Q. What pressure will be had in the brake pipe if the brake valve be left in release position?

A. Main reservoir pressure.

85.  Q. Can the locomotive brake be released by the automatic brake valve in release position, when using the H-6 valve?

A. No; as the port in the automatic brake valve to which the distributing valve release pipe is attached is blanked in this position of the valve.