On London commuter when going to Reigate, i think, I have encountered blinking signals. Instead of a steady green or yellow light it blinks. What is the significance of this?
It's called approach control when you are routed to a lower speed line. It gives you advanced warning that you will be required to slow down to the appropriate turn out speed.
Flashing yellows mean "high speed divergence, turnout set", ie you are changing lines at a speed above 30mph ahead and the switch is set This is as opposed to being brought down in speed by static yellows where the last signal before the divergence will be red until the signaller (or automatic systems) see the train being below the required speed for the turnout From what I've seen you must still be prepared for the last signal to remain red rather than "being prepared for it to change"
