I saw the club layout around 1979. I believe it was a well-established layout that went back many years. I visited EMD La Grange numerous times back then, several weeks in all to inspect new locomotives.
From what I can remember, the club layout was near an employee lunch room in the main factory/administration building. It was moderately large and had a three-track main line as a key feature with catenary over one of the main tracks. There was an operating model representing one of the white EMD experimental electric locomotives of the 1970's.
While I was in Chicago one time, a local TV news station did a short feature about the EMD model railroad. I distinctly remember a glimpse of a model GE loco puffing smoke, and guys smirking at it in front of the camera.
I haven't been able to find any pics of the EMD model railroad on the internet. Wonder what happened to it and if anyone here can tell us more about it?
In last photo, those are "exhaust mufflers" on racks at left, applied to new EMD locos beginning with 1980 models.