Blood tracks on a moose train

The story:

I was listening to the UNKLE album (which
I'd only recently acquired, but loved for
years when I'd heard it at my friend's) and
heard this lyric, and asked my girlfriend why
on earth they were singing that.. she
laughed and teased me about it for ages
but I just found out she was wrong too -
she'd heard "Blood tracks on a loose vein".