piston to the end of its stroke; just before the piston reaches the end
of the cylinder, the steam valve opens communication to the exhaust port
through a cavity in its exhaust side, then through the exhaust pipes and
tips up through the draft or petticoat pipe and stack to the atmosphere.
When steam pushes the piston through the cylinder, its power is
transmitted by the main rod to the main crank pin which causes the
wheels to revolve, thus moving the engine and its train.

7. Q. Why is it important that there be no holes through the smoke-box
door or front end and none in smoke-box seams or joints?

A. So as to maintain as good a vacuum as possible in the smoke-box and
prevent small amounts of air coming in through leaks which tend to heat
and warp the smoke-box and its door.

8. Q. How should the locomotive be started to avoid jerks, and what
train and other signals should be looked out for at the time of
starting?

A. Place the reverse lever in full gear, open the throttle valve
gradually so as to start the train one car at a time and easily. Look
for signals ahead to show that the track is clear and switch is in
correct position, then look for signals from the rear end that the train
is all coming.

9. Q. Will an engine equipped with superheat units move as quickly as a
saturated steam locomotive when throttle valve is first opened?

A. No.