The article says the engineer saw the man put something on the tracks - stopped the train & saw it was a little dog.
Engineers are trained to know how to stop their trains.
“Engineers are trained to know how to stop their trains.”
Yes, but trains are VERY heavy, and have some rather interesting challenges with traction thanks to their use of steel wheels on steel rail. Even at low speeds it takes quite a bit of distance to bring a train to a stop.
I agree with whoever posted previously that the train was probably not moving very fast. It also sounds like someone other than the engineer saw the dog first and alerted the engineer.