Deano,
if your engine house looks anywhere like this
it´s been manufactured by the Heljan in Denmark. They still make it!
Read that IHC out of Business years ago But they appear to be back
Company Profile updated 2-5-16
https://www.thespruce.com/international-hobby-corporation-ihc-profile-2382238
From above Found this website - No O scale - Site appears to be active
http://www.ihc-hobby.com/
Try contacting them or ATLAS. MTH enginehouse does not appear to be same kit.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
Thanks, Ulrich. I had a hunch it was Heljan, as I built several structure kits by them during the years I modeled in HO, even had some with extra parts I could use for other structure projects. I'm having a ball measuring and armchairing how to turn it into the Mineral Point & Northern Janesville, Wisconsin, engine house!
Deano