Huh. Yesterday evening, we got lucky and were called to deadhead back to Calwa via Amtrak 718. While we were on the platform at Emeryville, a light-power move cruised by us. It had two freshly painted SD-40 somethings and then four big jacks, but all of that was powered on the far end by two non-turbocharged GP somethings, one of which had the different style of UP lettering (it's a little more squared off, and I was once told that's the style of lettering chosen for ex-MOPac units..??)

Anyway, the move went back and forth a couple of times without doing any work, and I thought it was pretty cool listening to the GP somethings come all the way out as it got up to speed again. It seemed to me the only units on line were the old Geeps. I was kind of curious as to what the heck they were doing. Just went back and forth for a mile or so a couple of times. Was this part of what you're mentioning, OPPRMS?