Found this video and thought it may help us luddites understand whats going on. An area of modelling I am severly lacking in knowledge of. You mean they actually move I have to admit I have bought a couple of books on semaphore and colour light signaling for modellers, and don't be silly of course I've not read them yet Paul
Signalling is probably one of my favourite parts of it all, especially pre-grouping where complicated areas might have 4 or more boxes in the space of a few hundred metres. There is a decent book on the subject called "Two Centuries of Railway Signalling" which covers everything from flagmen to IECC control centres