He was a promising student but he 'went off the rails' after he started taking drugs.
The train went off the 'rails'. = ('chiefly Brit') The train jumped the 'rails'.
The workers 'railed' about the unfair treatment they'd received.
(..) All right, let's everyone take a break! You feelin' a little better? Yeah, I'm fine. Whoa! Grab the rail. Or don't. You've got three options. Hang there and I'll forget your cowardice. Fall and die. (..)2014 Divergent