Factual error: At the end of the movie, when the new time machine built into a steam locomotive begins flying and departing, the train signals are still running and the barrier crossings are still down. The train signals should have stopped once the flying time machine locomotive was off the tracks.
Suggested correction: Train signals generally stop once the end of the train is a good distance away from the road where the signals sit, by sensors. In the film, the train is too close to the road and by lifting up in the air, the sensor to stop the signals were never reached by the train.
Corrected entry: Doc Brown can build a time machine but is unable to figure out how to build a still to extract pure ethanol from Whisky in order to use as fuel for the DeLorean. He stated to Clara that he is a "student of all science" so this should include chemistry. Chemists know how to build a still. Doc, however, tried to fuel the car with strong Whisky without distilling it.
Correction: They did not have time to build anything, they were in a hurry to leave before Doc gets killed.
Correction: He would with no problem be able to get that thing to run on ethanol, just a different air fuel ratio bigger injectors so just make bigger holes in the ones you have. Just to run it one time would be no problem.
