Bachmann GP38-2

[faraway]

However, the old! Athearn RTR drive (motor and truck gearbox) is not worth the trouble and has been totally removed. The engines became dummys to be used with the Bachmann only at this moment.

Are you sure, or are you referring to the old Blue box drives? I know the RTR drives are fairly similar, but they have improved a bit in my opinion, the motor does need replacing, either with a Mashima (A-Line) or a NWSL repower kit. I did that for a GP38-2 I have (actually, that WAS a Bluebox unit, but I replaced the cab for a Cannon&Co one , it's actually the unit in my current avatar :-) ) , and it runs fine, including very slow speeds.

Koos

I did refer to the current not blue box Athraen RTR engines like GP38, CF7 etc. but not to the very new one with improved drive like SW1500.
I did remotor with A-line and Kato motors. A-line is a big disappointment because the flywheels are not factory mounted and balanced. The drive vibrates at all speeds above switching. The Kato motors with factory mounted flywheels are very quiet and a good choice.
The trucks are a problem too I could never solve. They do not isolate the engine vibrations from the rails. That is given by design and can not be changed other than mounting different trucks. You can test the ugly effect if you take an Athearn RTR chassis with trucks but no motor and an Atlas/Trainman chassis with trucks but no motor etc. Glue/nail a track on bare plywood and roll both with your hands. You will notice the difference immediately (you can mitigate the truck problem with a good track isolation on the layout).

I handle Athearn RTR therefor as follows:
- If there is absolute no other chance to run the model solo (e.g CF7) I install a Kato motor
- If I can MU (like in my CN GP38 case) it becomes a dummy
- Otherwise I refrain from Athearn RTR models

ps. There is a special situation with the RTR GP38-2 because the shell can be transplanted on a Trainman GP38-2 drive solving motor and truck issues.