I like the inside appearance. I can see you had the same problem that many of us had with the outside of the tunnel, in that the highlights are blown. It looks like you tried some burning to bring in details and got that yucky grayish stuff where there was no detail to bring in.
Something makes the top brick look like they are moving, sort of a cool effect. I would love to see this at night with some cool auto lights moving through it. Off course, you might not be here to submit the picture if you did it at night would you.