To shit trains typically means you are the shit. It can also correlate to being number one at everything. Often times used for upping a Mister One Upper, or someone who has to beat you at every event, activity, or story you've ever encountered.
by charlievato July 06, 2008
The cops was about to get my ass so I yelled, "I Shit Trains!" And by the power of the Unknown I shat a train that derailed another train and killed dem.
by Anonymous Train Shitter December 18, 2008