The car had an overheat condition. Weaver ignored the warning.
The list of things that were hokey in that movie is long.
When the gas station attendant told weaver that his radiator hose looked bad. Weaver blew it off, and went most of the movie without blowing the hose, in which case he could have been long gone.
But the movie portrayed the car as awkward and unable to escape a loaded semi. I remember years ago sitting in my truck at a truck stop one night. The cb ‘community’ was chatting away, and that movie was brought up. To sum it up, truck drivers regard the movie as ridiculous.
One thing that only truck drivers would notice was how agile the ‘loaded’ truck was, yet the trailer bounced and wobbled when going over bumps, indicating it was empty, yet shown to be loaded as it labored to climb hills.
I remember the techniques they used to show the ‘powerful’ semi closing the gap on him down hill and on the level. Slightly speed up the camera, and slightly apply brakes to the car.
I know that if a truck started pushing a car into a passing train, I think most anyone would at the least get out and get clear away of the situation. If it were me getting pushed into the train (as a truck driver), I would have jumped out of the car, hurried to disconnect the semis air lines to the trailer (can be done in a couple seconds). There he would have sat, unless he decided to fight without a truck.