LOCATING A MYSTERIOUS POUND.
Several years ago a very troublesome and mysterious pound caused the writer a great deal of annoyance. He was running an old engine, with cylinders that had been bored out until no counter-bore was left. The piston had worn a seat leaving a small ridge at the end of its back travel. The main-rod was taken down one day; and, in putting it up again, the travel of the piston was slightly altered. The engine started out with a pound, and kept it up. If any of my readers have been working an engine that seemed to hang together merely by luck, away on construction work on the wild prairies, with no machine-shops in the rear to appeal to for aid or counsel, with all his own repairing to do without tools or skilled assistance, they will understand the difficulty experienced in locating that pound at the back end of the cylinder.
A cylinder loose on the frame, or a broken frame, will jar the whole machine; and both of these defects are serious, and demand increased care in taking the engine along with the train. Loose driving-box brasses produce a pound which is sometimes difficult to locate. In searching for the cause of a pound, it is a good plan to place the engine with one of the cranks on the quarter, block the wheels, and have the fireman open the throttle a little, and reverse the engine with the steam on. By closely watching in turn each connection, as the steam through the piston gives a pull or a thrust to the cross-head, the defect which causes the pound may be located. Never run with a serious pound inside of a cylinder. It is an almost certain indication that a smash is imminent.