What is it?

Thank you Pete. SD50 sounds about right given the timeline too.
I've lived in Westmont and Downers Grove... I know that lovely suburb of yours very well. 91st Street to Mahoney road South, is the directions to my favorite Santa Fe haunting grounds.
 
That is one of the SD60 Demo units. IIRC, the SD50's didn't have demo units. We had the demo units on the UP, December 1984 in Northern California. That paint scheme was modified for the 100 units BN leased from the Oakway Leasing, which also were SD60's. Sweet picture.

Greg Elems
 
I stand corrected...

Found a photo of EMD 4, taken at a broader angle, and the last two doors were clearly there, right at the "EMD" logo. I thought that the demo scheme was also used for the SD50s, and I couldn't see the doors in the posted photo. Sorry 'bout that...
Pete