Locomotive Engine Running and Management

by Angus Sinclair

DATA NECESSARY FOR ANALYZING THE DIAGRAM.

In proceeding to ascertain from the diagram calculations of the work done by the engine, it will be remembered that vertical measurements represent pressures in the cylinder, and horizontal measurements positions of the piston. To understand the language of the diagram properly, it is necessary that several things having reference to permanent or accidental conditions be known. Those absolutely necessary are, the scale of the indicator spring, the diameter of the engine cylinder and stroke of the piston, the strokes made per minute, and the boiler pressure. It is also desirable to know the dimensions of steam-pipes, steam-ports, and exhaust nozzles.