HO / N scale - Krupp K5 series long range railway gun "Leopold".

thingiverse

This was my first 3D model railway project. The internet has some really cool, detailed models of the K5 long range Krupp railway gun, but I couldn't find one that was free and would print well in a hobby 3D printer (in fact needed less detail), so I had to give it a try. I love models and model trains, and this one is especially interesting because it's one of the most successful railway guns of WWII. It's big enough to have a terrifying caliber and small enough to be actually useful, with 12 axles that look great on the rails. This model is in N scale, but you can scale it up to 1:82 or 1:84 to make it fit HO size. I've found that it prints better in HO than in N scale.