Distant signal indicators

Relevant to page 117 in the book of Regulations for Train Signalling and Signalmen's General Instructions, seen here www.flickr.com/photos/192151030@N08/52446910117/in/album-... and similar to the one seen in Sleights West box www.flickr.com/photos/192151030@N08/52440002775/in/album-...

Done