drifting. If not kept clean they may stick open; when working steam the
engine will blow badly; if they stick shut the engine will pound when
drifting.

40. Q. In what position should the reverse lever be when the steam is
shut off and the engine drifting?

A. Below three-quarters of full gear, so the valves will have nearly
full travel.

41. Q. Why should the power reversing gear of the Mallet compound always
have its dash-pot cylinder full of oil?

A. To prevent the too rapid movement of the reverse gear piston and its
damage.

42. Q. In what position should the engines stand to test for blows in
valves and piston packing?

A. Put the operating valve, or starting valve, in simple position. Spot
the engine in the proper position and test each engine for blows the
same as for a simple engine.

43. Q. What power is used with Ragonnet or Baldwin power reverse gear?

A. Air pressure.

44. Q. Can and should steam pressure be used?

A. Yes. However, steam should never be used except in an emergency when