Compounding the issue!

ALTHOUGH compound steam locomotives were used by several of Britain’s pre-Grouping railway companies during the late 19th and early 20th centuries – notably the London & North Western, Great Eastern and Great Western (which sensibly bought three examples from France rather than build its own), their performance over simple-expansion types tended to be disappointing and in due course, many were rebuilt as ordinary locomotives.

Compound locomotives used high and low-pressure cylinders to maximise the use of the steam produced, firstly in a high-pressure cylinder (or cylinders) and then, rather than go to waste as exhaust before all of its remaining energy had been captured, in a larger-diameter low-pressure cylinder (or cylinders), potentially also bringing a big saving in coal consumption. In the marine environment, many steampowered tugs and larger vessels went a step further by adopting a triple-expansion arrangement.

The only British compounds