INDICATING SHELTER ON “CALDICOT CASTLE”
WHEN a railway has turned out a new type of engine, an early experience the first locomotive of the class has usually to undergo is a very thorough series of tests. The boiler has been tested under its full working pressure of steam, and some-
The “trial trip” is made with workmen hanging on all round, as you can see in the picture; they are armed with large oilcans, and charged with seeing that no part of the machinery “runs hot”, or develops any other kind of trouble. It is not until this trial is over that the engine goes into the paint-
ON A “TRIAL TRIP”
Later on there come some further and more important tests. Possibly you have, at some time or another, seen an engine with the front all boxed in, as in the case of the big Great Western engine, “Caldicot Castle”, at the head of this chapter. This shows that the locomotive is in course of being “indicated”. Indicating consists in obtaining curious boot-
The man who has charge of the indicating apparatus must be protected from the wind and the weather, as he rides on the front of the engine, and so these fine shelters are now erected to make him as comfortable as possible. The idea of indicating the engine is to see whether it is really working as efficiently as it has been designed to do.
“CALDICOT CASTLE” READY FOR THE TESTS
Other very important tests require the use of what is called a dynamometer car; you see some of the recording apparatus inside the Great Western car in the picture below. The chief object of this remarkable coach is to record exactly the “pull” exerted by the engine as it starts and draws along its train. So the hook of the car, to which the coupling of the engine is attached, is connected to a most complicated mechanism under the dynamometer car, which, by moving a pen, has the effect of drawing an unbroken line on a long roll of paper all the way through the journey.
The paper itself is slowly unwound by clockwork, and many kinds of other ingenious devices are used to mark on the paper all the mile-
DYNAMOMETER CAR, GREAT WESTERN RAILWAY
From Cecil J Allen’s Railway Wonders (1925)