Here's a paper model of a chemical container train car I've used as a prop in my Savage Cyberworld -campaign. Print it on two A4/Letter sheets, on cardstock, 120g paper or something else strudier than standard paper. I haven't added instructions as the model is quite simple, and I didn't see it necessary to add the parts that attach train cars to each other (whatever they are called in English), model worked quite well without them. It's a fast and easy model, round parts at the ends requiring perhaps a bit more thinking. You can see from the photo below how you should put the model together.
Also, I haven't seen it necessary to draw all cut & fold lines, just showing example - it's faster for you to draw them without accurate lines you try to follow.
Below, you can see the car in actual game. You can read session description for the scenario where the car was used, it has simple train yard rules for Savage Worlds, and can be easily adapted to other systems too: Savage Cyberworld; session 4