” I can easily see anyone panicking just before the final moment and desperately trying to undo their act. “
Or more likely, the conductor, realizing the train was going too fast rushed forward and pulled the brake.
That reminds me - I saw a pic of the engineer. He was wearing a railroad cap that said "CONDUCTOR" on it. Is that a proper cap for an engineer?....or more likely, it was a pic from when he was a conductor before he made train engineer.