Oh, come on! Everybody knows how simple it is to stop a train and drain a tank car.
I don’t know anything about TV/movies land...
But in my misspent youth, I did work on a cross-country pipeline.
Time is money and that pipeline costs a bundle, so move they product FAST.
The faster it moves the higher the pressure.
No pump would be needed to fill the tank car, most likely the hose would burst unless the flow was throttled.
And best secure that hose or it will whip around and kill you.