This query relates to a layout build recently started elsewhere on the forum:     This is based on a small ex-Midi secondary line in the 1950s. A year ago I knew nothing about French signalling, now I know a bit more - I'm not sure whether that is a good thing!   There are some articles on the internet including a Wikipedia page, and the current issue of the FRS magazine has a useful summary of the principles. There is also a Signalling Paper (No.13) available from the