While the "Back to the Future" trilogy was generally brilliant, its ending was a sentimental, illogical cop-out. Train smashes into car, destroying it -- AND DOESN'T STOP? Doc in the past uses steam to generate the required power for another time vehicle using only the resources available then? The list goes on and on, though frankly, the train not stopping has always been the big blocker for me at that point.
@lauren I always thought it was to have a callback to Doc saying that Biff's car would cut through the DeLorean like it was "tin foil" in the second one.
@powersoffour But nothing that follows makes sense due to this. In real life, the train would stop. Police and railroad officials and news crews would swarm the area. Everything would have been completely cleaned up immediately (including probably radioactive parts of the car). Etc.
Perhaps a more charitable interpretation would be that we're witnessing the breakdown of the fantasy -- this is when the real Marty dies. And what we see after is some gotcha twist ending that is his fantasy of what would have happened. (...nah.)
@lauren OK at the risk of extending this too far, I am now wondering about the fallout from the incident at Twin/Lone Pine[s] Mall in the first one. We see Doc and Marty go to a doctor, Marty sleeps the evening off ... but what about all the kerfuffle with the terrorists? Surely there should have been *something*, right?