Train in Vain (The Clash cover) Lyrics

Lyric discussion by TheseFights 

Cover art for Train in Vain (The Clash cover) lyrics by Glassjaw

I think he's talking about his girl doing heroin or shooting up something, then cheating on him and leaving him. "Train in vein", like the tracks that show up on your arm after you shoot up, trains run on tracks, get it?