A repeating signal or repeater is one placed to the rear of a signal in order to provide early indication of the indication of the signal. It is an advisory signal and therefore permissive and may always be passed. A repeater has only two positions, on and off. In the on position it indicates that the signal ahead which it repeats is in the on position or most restrictive indication. In the off position it indicates that the signal ahead which it repeats is off, i.e., not on (but not necessarily clear).