Barriers, signals and safe behaviour
A protected crossing has barriers, lights and a bell. An unprotected crossing has just St Andrew's crosses and possibly distance markers. At an unprotected crossing, you are the entire safety system — slow down, listen, look both ways before crossing.
Red flashing, barriers descending, or a bell ringing — you stop and don't cross until all three are silent. One train may pass, but a second train can come right after on the other track. Wait until everything is quiet.
Never enter a crossing if traffic ahead is stopped and you risk being stranded on the rails. With a trailer, caravan or long vehicle, account for the full length plus a safety margin. If you're unsure, wait before the crossing, not on it.
You only cross when you know the whole vehicle — including any trailer — can pass without stopping. It's not 'I'll have room soon'. It's 'I have room right now'.
The barriers are up, the lights are off, the crossing looks clear. But there's a queue of cars on the other side. If you drive in, you get stuck on the tracks. The train arrives in 30 seconds. No chance to clear.
Barriers are up at a level crossing. Traffic on the far side is at a standstill. What do you do? Stop before the crossing until you can see the way through is clear. Open barriers aren't a 'go' signal — just a 'no train right now' signal.