(19-07-2010, 10:56 PM)interesting_signal Wrote: with buffer stops when do you show a red light, or when do you show a white light or when is it appropriate to show no light at all?
Buffer stops should be red EXCEPT where the red light by night could be misinterpreted by a driver as applying to them; note that a red light exhibited in the cess could be a hand danger signal shown by a member of staff from a position of safety.
Hence where a driver would see the buffers as a red light facing them only one track width away from their line, then the buffer stop light should be white; typically this could be where there is a facing connection into a siding on the left hand side of the line, or a head-shunt from a siding that terminates in a spur. On a double track line, a siding in the opposite cess is not in generally perceived to be a problem as it is far enough away, although it is possible that line curvature could give a problem. Similarly a passenger platform buffer stop even very close to the line is not normally liable to be confused due to the presence of lighting and other visual clues in the area; hence these are almost invariably red.
I would expect that all buffers shown on a signalling plan would have lights, although perhaps those from the running line may not be lit. Note however that the lights aren't PROVED and, except in rare cases, are not fed from a signalling power supply. Historically they would have been parafin lamps; nowadays they are typically fed from a station power supply. We do still show them on a Signalling Plan where they are on or adjacent to the signalled railway.
PJW