Here's a project I've been working on. I found a Shcnabel car on Thingiverse. It's a German prototype so I heavily modified it and came up with this: Once I got it working I decided to go bigger: It still needs a lot of work but I wanted to make sure I could get it operational before I spent a lot of time on details and I've gotten it working flawlessly. I have come to a dilemma, however, do I finish this car or go even bigger? The largest rail cars ever are the KRL 3600 (formerly WECX 800 and CEBX 801) and KRL3601 (formerly WECX 801). They are 36 axle cars, compared to 32 on mine. I went with 32 axles just because it was easier (more symmetrical) and since it is obviously freelanced I don't have to try to get it as correct as if I was modelling an actual car. Now it's bothering me that I could go even bigger. I'll probably finish this one and then do a 36 axle car. I decided it didn't look right by itself and started adding support cars: Again, they still need work, especially the caboose, but they are works in progress. Currently, I have this: Everything except the engine, wheels, and a few miscellaneous parts is 3d printed, even the trucks and couplers. The parts that are not printed but could have been are a couple of washers, a piece of PVC pipe, and a couple of 5mm LEDs I used for ball and socket joints on the bigger car (it would have taken a lot of sanding to get them smooth enough if I printed them). You certainly can't get the detail that you can with commercial products, but from two feet away I think they look pretty good.