Power Signalling At Bristol
One diagram 6 ft. x 3 ft. is provided in the Loco cabin, two diagrams 15 ft. x 3 ft. in the West cabin, and three 15 ft. 3 ft. in the East cabin. These diagrams are the G.R.S. all steel type having the diagram hand painted on to a black matt finished planished steel front plate, each track circuit illuminated when occupied with two 12V 1.3W B.E.S.A. SL.19 telephone type lamps mounted in holders with red bulls-eyes. The lamps are removable from the front of the diagram for easy maintenance, and are factory wired on to terminal blocks.
The diagrams are mounted on the top of the locking frame with short chromium plated tubular steel pedestals which are used in addition as wire inlets. To prevent undue strain on the pedestals small ceiling brackets are also used.