Looks nice, layout looks solid and fun, detailing is nice without being overpowering and it's payload. What more could you ask for?
Also, I think it would be super awesome if you wanted to challenge yourself with your own custom bomb explosion for the final cap. Possible make the two pillars ontop of the cap hole area collapse into the hole and pull that whole crane structure with it, it would look badass and you could have the crane hit the train from above which causes it to explode.
Awesome but hard work.