You can start at this post where
@txlabman talks about Empire Red - though I am convinced that paint color changed in the last few years. There are some photos to look at too in that thread of the paint colors. I went from two cans a bit over a year ago and then last year it ended up being darker. Though there is a time frame of Empire engines and some accessories that were painted a darker red. I have a No. 92 "Play Boy" and two ferris wheels that are a darker color. Then I am sure the color varied through the years from the factory, then the engine's paint naturally changes over the years.
Yet another GIFT engine: Empire B-43Here is a YouTube of
@txlabman B-43's. I don't know if he painted any of them, they were painted by a PO or they are original. That said any of those shades of red would be good for a re-paint, IMO.