A little OT since it's not cab signaling but IRM has a great collection of signals in their signal row and over recent years most of them have been placed in operating condition. On occasion they have set up a PC where one can reset the signals by the click of a mouse.

http://www.youtube.com/watch?v=0G1ZC5-fUC4

I haven't seen them do this recently. There is now a South Shore sign located about where the computer is in the video.

Steve