(1) A calling-on signal is a subsidiary signal which has no independent aspect in the ‘ON’ position and shall be a miniature yellow light provided with a ‘C’ marker.
(2) A calling-on signal, where provided, shall be fixed below a stop signal governing the approach of a train. Under special instructions, a Calling-on signal may be provided below any other stop signal except the last stop signal.
¹Hkkx IIµ[k.M 3(i)º Hkkjr dk jkti=k % vlk/kj.k 165
(3) A calling-on signal shall be used when the signal below which it is provided is defective or to receive a train on an obstructed line since the main signal cannot be taken 'OFF'.
(4) A calling-on signal shall show no light in the ‘ON’ position.
(5) A calling-on signal shall except when permitted otherwise under special instructions detect all the points falling in the route which the main signal above it detects excluding those points which fall within the signal overlap.
(6) A calling-on signal, when taken 'OFF', calls on the loco pilot of a train to draw ahead with caution, after the train has been brought to a stop even though the stop signal above it is at 'ON' and indicates to the loco pilot that he should be prepared to stop short of any obstruction.
(7) The aspects and indications of calling-on signals are as shown below.-