At the end of the movie, when Marty and Jennifer arrived at the place where the DeLorean was wrecked by train, a few seconds before Doc appears in the steam locomotive version time machine, the barrier at the crossing falls down automatically, just as in any regular situation when a train approaches the crossing. Such type of barrier does not fall down if there is no train on the rail, yet it the movie it fell down before the locomotive appeared on the rail, when the rail was empty for a long distance in both directions.