There no way for a passenger or anyone to get inside the engineer while it’s in motion.
There are no doors or entry way into the engine from the passenger section of the train.
The only way for anyone to have gotten onto the engine was at the station or leaped onto the engine while going slow in the yards outside the train station.
“inside the engineer”
Well, he is gay!
Freudian slip?
CC
I think we’ll find out this was a suicide attempt and he lost his nerve in the turn, and hit the brakes.
Nothing else makes sense. He knew the route. No one claimed responsibility for a terrorist act, he wasn’t asleep, and he probably wasn’t texting or on the phone, and a projectile would not have caused an engineer to panic and speed up.
Pure speculation, but that’s my opinion at this point