HOW TO USE SAND.
The first consideration in this regard is to have clean, dry sand, and easy-working box-valves. Then the engineer should know how far the valves open by the distance he draws the lever. In starting from a station, or working at a point where slipping is likely to commence, the valves should be opened a little, and a slight sprinkling of sand dropped on the rails. This often serves the purpose of preventing slipping just as well as a heavy coating of sand. And it has none of the objectionable features of thick sanding. Trains often get stalled on grades by the sand-valves being allowed to run too freely. It is not an uncommon occurrence for engineers to open the valves wide, and let all the sand run upon the rails that the pipe will carry, so that a solid crust covers each rail, and every wheel on the train gets clogged with the powdered silica; and, after the train has passed over, a coating is left for the next one that comes along.
The wheels scatter their burden of powdered sand into the axle-boxes, and it grinds its way inside the rod-brasses, and part of it gets wafted upon the guides; and in all these positions it is matter decidedly in the wrong place. And this body of sand under the wheels increases the resistance in the same way, as a wagon is harder to pull among gravel than it is on a clean, hard road: the indiscreet engineer complains about the train being stiff to haul; and the chances are, that he goes twice up the hill before the whole train is got over. Uncle Toby’s plan is, when pulling on a heavy grade, to open the valve enough to let the drivers leave a slight white impression on the rails. If they slip, he gives a few particles more sand, but decreases the supply again so soon as the drivers will hold with the diminished quantity. Uncle Toby seldom needs to double a hill.