GGG, I have PS2 F series AA units on my G scale track with straight DC power.
I turned on the transformer and raised the handle too much. The units moved right away.
I lowered the voltage and they just sat and idled. As soon as the voltage is raised just right amount, they go forward.
Is that what you needed?
I think the main difference is the engine is in forward and just doesn't move. When you throw the direction switch, it is in reverse, yet doesn't move until voltage is raised. It doesn't appear to be stalled, just that it's in one direction or the other and so are the lights.
I don't hear any motor hum, and there seems to be a threshold where the power starts going to the motors.
It does seem very touchy about the amount of voltage to decide to start moving. My throttle might not be capable enough. A slight touch, and the engines move very slowly. I usually run in command mode, so this is different for me.
