What is meant by the flashing white light?
The Road Sign Ordinance states that: “Beneath the red light apertures there may be a circular aperture from which may be emitted a flashing white light in order to make the crossing easier to detect.”
The flashing white light does not guarantee anything. You must always be extremely careful and attentive when driving over a railway crossing.
A train will never have an obligation to give way to you: “A road-user must ensure freedom of passage for [...] railway trains” (Road Traffic Ordinance).
But surely the signal will be flashing red if there is a train coming?
– Usually, yes. However, a collision with a train is extremely dangerous. You may never relax and think that you have the ‘right’ to drive across. If a train should come now, you have a legal obligation to stop – even if there is a flashing white light and the barriers are open.
More examples of explanations: