At the risk of being the rivet counting jerk, that sounds like a 645 turbo prime mover, I think the GP35 was powered by the earlier 567 (also turbo in this case). This is nerd-level stuff I'd have never known if it wasn't for DCC sound systems! Either way, probably an easy programming fix. Or I'm wrong!
I knew Dick well and operated on his RR many times. His passing brought much sorrow and I;m so glad I got to know him as well as I did. His RR was one of the best if not the best.
Message to all the videographers creating model railroad tour videos.....sloooooow down your camera panning. Let everyone see the incredible skill and detail on these layouts. The camera movement is so fast that images look fuzzy at half speed and even on pause.