A. The operating rod located on the back-head of the locomotive boiler—if the piston is making a power stroke—should be moved to its lower position, and if the piston is making a return stroke, it should be moved to its upper position. This moves a small valve in the auxiliary head, bolted to reverse head, and steam is admitted to opposite head of cylinder, causing the piston to change its direction. The return of the operating rod handle to a central position causes the driving engine to resume its normal operation.
13. Q. How can the fireman observe the condition of fire in fire-box?
A. The elbows are provided with peep valves with swinging covers through which the coal supply and condition of fire may be seen.
14. Q. Why are two gauges necessary?
>A. The driving engine gauge on the left indicates the pressure of steam used by the driving engine. The one on the right has two indicators, the red indicator showing the steam pressure on the jet in left elbow, and the black indicator showing the pressure on the jet in the right elbow.
15. Q. When train is standing on siding for a short period, what should be done?
A. Shut stoker off by throwing operating rod on back head of locomotive boiler out of running position.
16. Q. When train is to stand for a long time or engine is left at terminal, what should be done?