My son got Thomas the tank engine for his third birthday... and of course Annie and Clarabel, the passenger cars. But he also wanted to have some freight cars, too. So daddy improved his OpenSCAD skills and designed a matching freight car. And here it is for all of you! It prints as a kit with 21 parts and it's quite a lot of work to clean all the parts and put them together, but in the end you get a nice working model. The cars are very light, so it is useful to add some weight to prevent derailing. Have a look at the colored image to see where all the parts are located. I used PLA to print and CA glue to put the parts together. My axles and coupler bolts were made from 1mm brass wire.