When one's penis is not at full erection and it bends in half when insertion is attempted during a sexual encounter, like a train wreck. Usually the result of nervousness, over intoxication, lack of viagra, or other reasons unknown.
Yo bro, Last night, after drinking 12 pabst blues at your double wide, I amtrak dicked off that chicks labia 4 times before she finally called me out. She all like piece out, don't forget your shoes.

Dude, I had Amtrak Dick so bad last night, there were no survivors.
by kungfumermaid June 8, 2015
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