"Sticky" Schools Class

[doug22150]

I have a different issue with my 4th Schools Class purchase, Malvern, from the Collectors Club Spring 2020 Offers I have been running it in and it is apparent that it suffers from a tight spot but only when running round curves. My minimum radius is 300 mm, which the loco. should be able to take with ease. On the straight, running is good but on curves there is a rhythmic "rubbing" and at times the loco. can be seen slowing and surging again as the "tightness" is passed. I have tried running without the front bogie and that completely eliminates the noise, as well as any tendency to "surge"! I've also checked the bogie wheel back to back dimensions, in case they might be rubbing on the valve gear. I think that the problem might be because the leading driving axle does not move smoothly from side to side. It can be felt to almost grate in the bearing (or gearing?) as it is pushed from side to side. This is quite different to the easy movement on the rear driving axle. I have tried lubricating the axle on each side but am very wary about over-lubricating.

Regards

Doug

[Andy Dapol]

Hi doug22150 ,
I also replied to your previous post, so will place it here also.
Hi doug22150 ,
It's tricky without being able to see the model. Certainly 300mm should be OK for this model. My initial thoughts are:

1. Check the alignment of the motion in case it's slightly bent inwards and is binding
2. Check the sideplay of all wheels is free - you mentioned this is an issue with the leading driver.

You are right to not over oil. If a little more judicious movement and check does not reveal anything obvious, unfortunately I can only suggest return to the place of purchase (Us!) or to DCC Supplies for warranty servicing.

[doug22150]

Thanks Andy
I have already checked the motion alignment and can't see anything out of line. I could try removing the cover plate on the underside of the loco., But I know from my previous experience replacing the brass bush under a Schools footplate that it's not easy. You advised that it clips in at the front but I don't want to risk damaging anything!
Regards
Doug

[Andy Dapol]

Hi doug22150 ,
I understand, unfortunately I don't have access to any Schools models at the moment (working from home) so I can't post any photos. If you are at all concerned about going any further then please send it in. Its not an issue which jumps out as being a particular cause, but I'm sure a quick check by DCC Supplies will sort it out.

[doug22150]

Thanks again Andy

[doug22150]

Hi Andy. I didn't manage to remove the cover plate despite levering underneath the front end gently. I also applied a little more oil on the end of a thin wire to the axles. That actually seems to have improved things and the axle does now slide from side to side far more freely. After some further running the slowing and surging motion is much improved, so looking more promising now.

Regards
Doug

[Andy Dapol]

Hi Doug,
Good to hear, sounds like it may have bee something that was a little over tight. Hopefully it should loosen up further during running. Let me know if it causes any further issues.

[doug22150]

Hi again Andy.

I'm afraid that I'm still having an issue with this loco.. I was happy enough after further running in April to install DCC but not the Dapol recommended way, so have probably invalidated the warranty! I decided to hard wire using a Zimo MX616 and install stay alive. This all fits in well and after testing on my programme track, I achieved excellent running on a rolling road. The loco. runs smoothly and very slowly ,starting and maintaining a slow crawl on speed step 1, with no binding or obvious tight spots. However, when it is placed on the track, it is a completely different matter! The loco.stops frequently and will not maintain a steady medium speed: tending to stop and stutter.

I've just separated the loco. and tender to carry out more testing. Standing alone, the motor drive will maintain a crawl speed with no stuttering. When it is pushed gently along, the motor continues to turn with no hesitation. So even just the tender unit doesn't have a pick-up problem. I also tried turning the loco. wheels by hand, placing a narrow screwdriver into the drive yoke. There is no obvious tight spot but the yoke doesn't seem straight on the worm shaft and does wobble as it is turned. Finally, I reconnected loco. and tender using just the drive shaft (without replacing the loco-tender pick-up wires). Unfortunately, with loco. and tender together, the running is still not satisfactory.

My next step will be to try swapping the tender drive from Malvern to another of my Schools locos but I am coming to the conclusion that the issue does lie with the loco.. Can you provide any further guidance on removing the cover plate from the bottom of the loco? You explained before that it should unclip but I'm nervous about going about this the wrong way and causing damage.

Regards

Doug

[Andy Dapol]

Hi Doug,
Sorry hear this. Its probably best to return it for a service to DCC supplies. (info (@) dccsupplies.com) As long as your decoder installation is not the cause then your warranty for the remainder of the loco is safe

[doug22150]

Hi Andy

Thanks for clarifying the warranty situation. The testing with another of my Schools confirmed that the decoder/stay-alive installation hadn't caused any problems. When it was attached to a different loco., running was very smooth and quiet, with no faltering. I will contact DCC Supplies to arrange a service as you suggest.

Regards

Doug