What kinds of signals (semaphores, lamps, etc.) does IR use?
IR uses several kinds of signals. Semaphore signals have generally given way to colour-light signals although there are still many places with semaphore signalling in use. [1/02] Semaphore signals are the older style signals seen widely throughout the country, where each signal has an assembly with an arm mounted on a mast, where the arm can move through two or three different positions at different angles, each position providing a distinct signalling aspect. Very early in India’s railway history, two-position lower-quadrant semaphore signals were the most prevalent. Around the 1930s, however, the introduction of American style power signalling equipment in some areas resulted in three-position upper-quadrant signalling being introduced as well, although both systems continued in use for many decades afterwards. It is not clear when distant signals were introduced. Colour-light signals are assemblies of lamps that indicate different aspects by means of different colours of lamps that
