Chuck, maybe it's my far less than perfect track work, but when I have run non-speed control engines and have them pull operating cars with sliding shoes through 022 switches, the train tends to run faster and less smoothly through the switches than when running a slow and smooth speed control locomotive.
In my experience, a sliding shoe of an operating car was much more likely to get snagged when the car was pulled by non-speed control engines like a Postwar or MTH PS1 locomotive.
