10. Q. Why?

A. Because steam must first pass through superheat units before it
enters the steam pipes leading to steam chest.

11. Q. In placing engine on the turntable, at water or stand pipes, or
at other similar places, what must be done?

A. Close throttle valve sooner so that the steam confined in superheat
units, pipes and steam chests, will have passed out to the atmosphere.

12. Q. After a locomotive has been started, how can it be run most
economically?

A. By regulating the supply of steam to the steam chest with the
throttle and the point of cut-off with the reverse lever; so that no
more steam be used than necessary to maintain the proper speed, whenever
possible working the engine at short cut-off so as to use steam
expansively.

13. Q. What is meant by working steam expansively?

A. Hooking the reverse lever up toward the center gives the valve a
shorter travel and closes the live steam port when the piston has made
only a part of its stroke. This cuts off the supply of live steam coming
from the steam chest. The expansion of the steam already in the cylinder
pushes the piston to the end of its stroke without the use of a full
cylinder of live steam.

14. Q. How rapidly should water be supplied to the boiler?