This one is a 3 bay and scales at ~33'

If you're going to pull this together be aware that the truck/coupler setup may be a little different than you're used to. After screwing around with clip on coupler covers and plastic pins for far too long, I've developed my own approach that uses a 3mm countersink head screw for attaching the trucks and a 2mm black panhead screw for attaching the coupler covers. The 3mm screw allows the truck to float around ever so slightly and the coupler box/cover work really well with Kadee whisker couplers.

Assembly is pretty straight forward, but if you have questions please ask. I throw some supports along the jutting sides of the trucks to get super clean prints, everything else prints support-free. 

I print these with a 0.25 nozzle and 0.15 layers to get all the fine detail.