I dont know if engine bodys are streyne plastic or not  but I use castrol super clean to strip bodys and works really well and dose not hurt the body. I do car modeling as well and this is what I use for it, never tried on a engine body.
Just a thought.
Kenny

I am making this for my wall layout  N&W. I am going to be using flex track to get 24 to 26 radius. I like using it cause you can compare. Put a cpl coaches on and see if you need to adjust. Or same with the engine I like to give it a little leway on the turns meaning not putting the trucks and wheels to the max while turning. It works so you can get it just right and is good to use for in between radius pre made track.
Kenny.

I understand plus I can get some great deals on ebay for it to. The room is only 7 foot hight but I see what you aare getting at puse I run some wd40 sprayed on a cloth and I wipe the tracks Helps clean and gets rid of jerky operation. Depending on how musch it is ran I  had a small round table lay out and I did this once a week. Ussaly ran about 2 hours a day.
Kenny

Ok I didn't think it would hurt being indoors, but the nickel silver woud hold up better.
Kenny

I was wondering this track the steel alloy wont have a problem in my house. It will be used for my sons and daughters wall trains for there rooms. I am setting up the thomas and friends in there rooms.
Please let me know
thank you
Kenny.