What is M-train?
1.
v - to drop from a difficult major like engineering or a science and switch to mangement.
See also Tech Trolley
Most of my friends dropped Computer Science and hopped on the old M-train.
2.
a girl's period.
she's crazy, and to make it worse, her m-train hasn't come yet...let's ditch her and egg some random persons house because we're brainless idiots!