Looks great! I’m a big fan of COP so I appreciated that vintage tank car.
Where did you source the piping and hoses?
The piping is from Walthers Cornerstone HO Piping Kit which has dozens of pipe pieces, elbows, connectors, etc. They look good in O scale. The kit includes stairs and hand railings which are HO scale , so too small to use, but the kit is worth all the piping.
The hose is spaghetti! I place it in room temperature water and let it soak until soft. Then arrange it to the shape I want and let it dry out. Then paint it. Be careful if using water based paint. If you brush too much, the surface of the spaghetti will soften and get gooey. I put on a quick coat, let it dry completely, and then do a second coat if needed. The spaghetti lets you make bends that look more natural than using plastic tubing.