I really like this shot. Unfortunately it doesn't convey the "straight lines only" message as strongly as some of the other entries. It's very well composed. Simple yet eye-catching. I'll give it a a 7, but would've been 8 if it expressed "straight" a bit stronger.
Its a joint. The lines behind from the sleepers though help this photo, as they run the opposite direction. Shallow DOF does work here, as does the B&W and the border