Basic Guide to Modern UK Railway Signals
This page is intended to provide an illustrative guide to common UK rail signals which are often used today. This guide doesn’t give information about semaphores as these are being phased out, but provides interesting information about coloured signals, ground and shunt signals. If you notice any mistakes, please get in touch. This guide should not be replied upon professionally.
Standard UK Railway Signals
A green signal means the upcoming section of track is clear, and the train is safe to proceed at line speed. A flashing green signal was historically used between Peterborough and York on 140mph section of track. A sold green signal would have meant the following signal was double yellow as below.
A double yellow signal means that the upcoming signal is a single yellow aspect, and the driver should be cautious and ready to slow down if the next signal is a single yellow aspect. A double yellow aspect would mean that the signal two sections away is red.
A yellow signal aspect indicates caution, because the next signal is likely to be set to red. The driver should slow down and prepare to stop before the next signal.
A red signal aspect indicates danger ahead, and the driver should stop before the red signal. If a driver proceeds (SPAD – signal passed at danger) through a red signal, the emergency brakes will be applied automatically.
Diversions and Route Indicators
A flashing double yellow signal aspect means that there is an upcoming diversion ahead. The following signal will be a flashing signal yellow, followed by a solid yellow but with a lit route indicator arm.