gauge indicates main reservoir pressure; on
the small gauge, brake cylinder pressure.

7. Q. What does the black hand on each of the air gauges indicate?

A. The black hand on the large gauge indicates the equalizing reservoir
pressure; on the small gauge, brake pipe pressure.

8. Q. What pressure is usually carried in the main reservoir?

A. Ninety pounds in freight and 130 pounds in passenger service. But
where freight engines are equipped with duplex compressor governor, the
low pressure top is adjusted to ninety pounds and the high pressure top
to 130 pounds.

9. Q. What pressure is usually carried in the brake pipe?

A. Seventy pounds in freight and 110 pounds in passenger service.

10. Q. What must the air pass through in flowing from the main reservoir
to the brake pipe?

A. Through the automatic brake valve.

11. Q. Name the different positions of the automatic brake valve.

A. Release, running, lap, service and emergency positions. The brake
valve used with the E. T. and L. T. equipment has still another position
known as holding position, which is located between running and lap
positions.

12. Q. Name the different positions of the independent brake valve.

A. Release, running, lap, slow application and quick application
positions.

13. Q. How many kinds of triple valves are there in use?

A. Two; plain and quick action.

14. Q. How is the automatic brake applied? How released?

A. The automatic brake is applied by a reduction of brake pipe pressure,
and is released by restoring the brake pipe pressure.

15. Q. When the independent brake valve handle is placed in application
position, are the train brakes affected?

A. No; only the brakes on the locomotive are applied.

16. Q. What controls the pressure in the main reservoir?

A. The compressor governor.

=EXAMINATION QUESTIONS=

SECOND SERIES

1. Q. What, in your opinion, is the best way to fire a locomotive?

A. To carry a nice, level fire on the grate, or it may be just a little
heavier at the sides and front, so the air cannot come through it near
the sheets as rapidly as in the center of the fire-box; always fire as
light as consistent with the work required, endeavor to maintain a
uniform steam pressure at all times, and avoid unnecessary black smoke
and a waste of steam through the safety valves by the engine popping.

2. Q. What are the advantages of superheated steam over saturated steam
in locomotive service?