Wagon added, hope you guys will like it.

Do it if you can just grab an oil tanker car and change it a bit

Sorry, I didn't plan for trains. in RL there isn't train-size volume to be carried. it is all done by trucks :-) Only processed, non-hazardous waste goes to the landfill by train.
I'll think about it, but I can't create wagon from the scratch by myself (not enough artistic talent to create 3D model), all I'd be able to do is to take one of the vanilla garbage wagons and slap the biohazard sign on it. I'm not sure if people would like that, though.

sooo, can trains carry dangerous biohazard materials too?