Flag; Red flag as provided in cab emergency equipment

Flags were provided to give clearly visible hand signals on the railway. In general they were used in daylight with oil lamps for use at night or in poor visibility as an alternative to red, green and yellow hand flags. The use of hand signals by flag or lamp was controlled by rules and regulations which covered when, where and how the signal was to be made and this varied according to the grade of staff that would be using them.
For example: Guards were provided with a green flags to control the starting of their train as a signal of 'right away' with red for warning anyone of danger if the train were not to be started, stopped it in an emergency or mark the rear of the train. On the underground tube lines flags and handlamps were mainly for emergency use as bell signals and an intercom were the main means of quick communication with the driver as his cab was often just in the tunnel.
Platform staff would use a white light or hand signal to indicate to the guard that a train was ready to leave. On the underground a green signal was shown to the guard when the last train of the day was permitted to depart.
Shunters would use a lamp waved in a particular way at night to indicate the permitted direction of a train movement.
A red light waved violently (or any colour in an emergency) would indicate to train crew to stop the train immediately.
A handsignalman would be appointed to control trains past a failed signal using red and green flags (or a light at night) or use yellow if a speed restriction were in place.
Flags were provided in train emergency equipment lockers for drivers or other crew to signal to other railway staff if the need arose on a journey.
Oil lamps were gradually phased out from the 1970s when the purpose made 'Bardic' electric handlamp became availalble. Like the oil lamps that preceeded them they were made in different versions depending on what colour aspects were to be availalble to the person issued with the lamp.