Re: NNG: Rio Grande std. gauge steam

Gavin is right. These shelters would be put on engines being tested for performance. The indicators had to be operated manually to read the "mean effective pressure" of a single stroke of the cylinder when the dynamometer car signaled for a reading. After the test run, the pressure readings would be combined with the drawbar pull and speed recorded by dynamometer car to come up with indicated horsepower readings, and the overall efficiency of the locomotive. After each reading, the operator had to file the paper showing that reading away, place a new slip of paper on the indicator drum and wait for the next signal. Since they were dealing with little slips of paper, the shelter had to be pretty well sealed up against wind, i.e. hotter than hell. By all accounts, a pretty miserable way to spend a day on a steam locomotive.

Indicator book



Edited 1 time(s). Last edit at 09/10/2007 02:02PM by Kelly Anderson.