What do the rings, bars, etc. found on some signals mean?
Stop signals controlling the approach to goods yards or goods-only lines have a black ring fixed to the end of the semaphore arm. No corresponding indication is provided in colour-light territory. Similarly, semaphore signals controlling lines for dock platforms have a black semicircle (in the shape of a ‘D’) fixed to the end of the semaphore arm. Again, no corresponding indication is provided for a colour-light signal. Two crossed bars in the form of a large ‘X’ attached to a signal of any kind (stop signals, shunt signals, etc.) indicate that the signal is not in use. The cross is often white for signals that have not yet been commissioned.
