system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What causes trucks to get stuck on railroad crossings?
gpt
Often it's the grading (sideways tilt) of the railroad track which is at odds with the layout of the road, creating what's effectively a large bump in the road. Grading is needed to keep the trains stable in turns. Vehicles long enough that two sets of wheels can sit on either side of the bump, can get the bump jammed up their undercarriage. Shorter vehicles are lifted by the bump and roll right over.