It's a diorama. A train just happens to run through it, that's all

welcome to the fourm!
now oversized doirama eh? well; i think i can help my "oversized dio" is four 4X8 sheets of 1/4" plywood it dipicts a 1/72nd scale WWII canadian airbase, military, shipyard and of course a town my and my buddys have been working on it for probably 3years now and it has planes from the americans, canadians,russians,germans,brits and many more! as for you mystery/ crime scene dio i cant hel you out but id thought id mention that your not alone in the world of large scale modelling!!
so good luck and i know for sure people here will beable to help (im not the most reliable!) welcome to finescale!

If your looking for buildings, you might want to try plastruct.com

what about a church with a grave yard or the delapitated building with a few freshly dug graves in the garden . Maybe a place thats overun with Zombies , limbs and stuff missing. Games Workshop do some skeleton warriors you could adapt for the church.