engine runs most of the time, instead of setting them with the lever in full fore-gear.
The valves are also tried for “back-gear,” in which the engine runs tender first. In the case, however, of tender engines the running done tender first is comparatively small in amount and the setting of the valves in back-gear is sometimes left, unless the inequalities between the front and back of the cylinders is very pronounced, in which case some adjustment is made to the back eccentric rod which may involve a slight alteration of the steam distribution in fore-gear.
Finally, when the valves have been set, the positions of the crosshead, which are equivalent to those of the piston, are measured on the slide bars corresponding to the four points: (1) steam cut-off; (2) exhaust opens; (3) exhaust closes; and (4) compression begins. Owing to the obliquity of the connecting rod these positions are different for the outward and inward strokes of the piston. A record of these measurements is kept for every engine.
