Another camera from inside the carriage catches Mr Szymanski warning other passengers, before crouching down himself and grabbing onto a hand rail with seconds to spare before the train hits.
The footage then captures the moment the train and truck crash into one another, smashing the front of the train and shattering the glass windscreen.
Talking to Polish broadcaster TVN, Mr Szymanski said the quick reaction of those on board was the reason why no one was harmed: "Passengers reacted in the right way. They got on the floor on command immediately."
Krzysztof Ryfa, a director of railway company Przewozy Regionalne, said: "He almost certainly saved passengers from injuries."