If a train is approaching a railroad crossing, the law in most jurisdictions—including the US and UK—requires you to stop your vehicle between 15 and 50 feet from the nearest rail. Stopping closer than 15 feet puts you in a "danger zone" where the train's overhang or a potential mechanical issue could strike your vehicle. Conversely, stopping further back than 50 feet can obstruct traffic behind you and may prevent you from having a clear view of the tracks to know when it is safe to proceed. This safety buffer is critical because modern trains are massive and cannot "stop on a dime"; a freight train moving at 55 mph can take over a mile to come to a full stop. You must remain stopped until the crossing signals stop flashing, the gates are fully raised, and you have checked both directions for any secondary trains that might be obscured by the first one.