HOW THE ENGINEER DID HIS WORK.
The engineer exhibited remarkable skill and intelligence in handling the engine. The water was carried steady without any fluctuation, which enabled the fireman to maintain the steam at an even pressure. Where the speed had to be reduced, no more braking was done than was absolutely necessary; and the brake was applied so gradually, that it was hard to distinguish that the speed was not being reduced merely through natural loss of inertia. Every time the steam was shut off, the links were dropped, giving the valves full travel. Many engineers do not recognize the urgent necessity for doing this. They will shut off steam, and leave the engine running hooked up, a practice which proves destructive to valves, their seats, pistons, and cylinders. Take the case of this engine cutting off at six inches of the stroke. As the piston moves from the point of cut-off to the point of release, a partial vacuum is formed in the cylinder; and, as soon as the valve opens the exhaust, the hot, cinder-laden gases from the smoke-box rush in through the nozzles to fill the void in the cylinder. During the return stroke, compression begins about eight inches before the completion of the stroke; and, as the compression is too great for the valve to hold down, it is jerked violently away from its seat, causing the clattering so well known where engines are running hooked up after the steam is shut off. I have known several cases of valves getting “cocked” from this cause alone.