Like Todd said, the Rail Chief line was produced by MR Equipment Corp. on W. 45th in New York. They made everything from rolling stock to track laying supplies, to structures and even farm animals under that brand.
Here are a few ads that appeared during the late forties and early fifties. The first ad is the oldest when they were located on 42nd St, before they moved to their more famous basement location on W 45th.
I wouldn't be surprised if the aluminum extrusions were made for them by the outfit Marty mentioned in Herkimer, New York (east of Utica), more famous for the Herkimer OK Streamliners in O and HO and/or Kasiner.
Jim