Rough running

Model Railroader Layouts and layout building
1

Good morning all. I spent some time trying to solve this problem last night and while it’s been improved, it still plagues me. I’ve got a DC layout, block controlled running off an MRC 280 throttle. I have two Atlas GP7s I got off eBay that have generally run pretty well. However, both ‘stutter’ on the tracks. At certian points they seem to slow down and sometimes stall completely, althought not regularly. The degree of the stall seem proportional to the speed. The faster it goes, the less noticable the stall. I wonder if this could be:

  1. Engine issues. I took apart one of the GP7s and cleaned the trucks and contact strips. While it made some bits cleaner (especially the contact strips), it doesn’t seem to have helped the problem.
  2. Track issues. I’ve both cleaned it with a track cleaner and tested the path. I’m getting the same voltage out at the rails as out of the transformer, so I don’t think the track is shorting or overly dirty.

I’m stumped, baffled, and somewhat frustrated about all this. Any input would be greatly appreciated.

2

Have you checked the motor? If your brushes get covered in gunk, no amount of lubing or track cleaning will help. Open frame motors are easier to clean both the brushes and the armatures.

3

While you are looking at the brushes and armatures, you can also take a look at the amount of play there is in the shafts from front to rear. Athearn motors have a lot of “play” in them that can be a problem over time.
Will

4

Hadn’t thought of that, but I’ll definately give it a try. I assumed that if the voltage was getting in then everything was okay. What’s the best way to clean the motors? I used rubbing alcohol and cotton swabs for the trucks and contact strips and that seemed to work well.

Thanks.

5

Thanks for your input about my questions on DCC and PC’s.

I have had experience in refreshing armatures that get “gunked”. The q-tips and alcohol should work fine. Also make sure that you are not down to a stub in the brush. If the only remnant of the brush is the stub that fits in the spring, you will get intermittent contact AND MORE IMPORTANTLY you are about to damage the armature. IF you have any “burned” in damage on the armature, using the finest emery paper that you can find, CAREFULLY restore the armature to a clean, smooth polished surface - avoiding any contact with the wires/connections. This is risky, but you are basically trying to recover a “used-up” motor - so what’s the risk?

Don