Issues with drive shafts in Dapol n gauge locos

[andreas]

Hi all,

 

Over the last few months I've been tempted into buying a number of Dapol tender locos. They are absolutely gorgeous models but I have been struggling to convince any of them to run adequately. Almost all models were second hand from a variety of sellers, both private and professional. With second-hand you always expect a few duds but getting 10 in a row seems unlikely and I'm slowly coming to the conclusion the problem must lie with me.

 

The models in question are 5x 9F, 2x Britannia, 2x GWR 2800 Class. What they all have in common is that the motor turns okay by itself but it struggles to move the wheels at a reasonable speed. For some locos the wheels will barely turn even when applying a higher voltage and trying in a cradle off the track. I'm used to have locos run pretty fast at 5V but for my Dapol locos I get maybe 5rpm at best even at higher voltage - of course complete with the screaming of a struggling motor.

 

Out of all the models the 9F moved the best, but they are still far from smooth runners and feel too slow. My real problems start with the Brits and 28xx whose wheels struggle to move at all. For one of the Brits I have already replaced a slightly bent cardan shaft but that may be a symptom, not the cause. This particular one can be convinced to run at higher speeds when cranking up the voltage. However, its tender will run so wobbly and jerkily that it ends up jumping off the track.

 

So far I have checked if perhaps the valve gear or con rods jam but I can't see anything obvious wrong. I have detached and reattached the drive shafts and also oiled the con rods and gears - all with very limited success.

I would appreciate any pointers to what else I should check or try. I've tried to search for corresponding topics here on the forum but I can't seem to find the right keywords.

 

Thanks in advance

 

Andy

 

[Les1952]

It sounds that inside the loco gearboxes what should be light oil has turned to a sort of oil-coloured cheese.  This happens if an oiled loco has stood idle for too long.  I've just been going through the Hawthorn Dene/Croft Spa stock, none of which have turned a wheel since lockdown in March and a couple have become very stiff.

 

There are two fixes that can be tried.  

 

Firstly, get a free-flowing long needle oiler and shove the needle as far into the aperture by the far end of the drive shaft as possible and apply a fair amount of oil.  This oil will mostly land on the worm.  It is possible to over-oil here but IMHO difficult to achieve.  Then run the loco backwards and forwards on a fairly high throttle until it eases, or use a rolling road, which is something I don't have.

 

Secondly remove the body, which on most Dapols is done by undoing the screw holding the front bogie/pony truck on then undoing the screw revealed.  You can then pull the body upwards making sure you don't grab the chassis by the valve gear as that doesn't improve it...   You have now a good access to oil the worm.  You can use tissue paper and/or a cocktauil stick to get rid of any oily cheese then lubricate the worm from above.

 

I've used method 2 with B1s and A3s, partly as doing two at once allows an identity change if one needs to go for a service at DCC Supplies.

 

If neither works then a service at DCC Supplies will fix the problem.  Describe it to Fiona as a "de-gunk" and she will know exactly who suggested you contact her.

 

Hope this all helps.

Les

 

[Chris M]

Les' advice sounds very good to me. Whilst the Dapol drive system does need careful handling it does usually work reasonably well.  I have noticed that leaving these locos in store for a long period is generally not good for their running but they usually come to life after a few laps of my layout. I find that the more they are used the better they run. The only thing I would add is to make sure that the cardan shaft is fully located in the loco and then slip it into the tender drive. If the shaft is not correctly seated it can cause the tender to wobble itself off the track.

[Chris M]

Another common issue, but one which doesn't cause the symptons you have, is broken wires between loco and tender. Its best to check that these are ok if you want to get good running. I have replaced quite a few of these wires. My Manor and Grange are much higher mileage than the others and also seem to be the best runners.

 

I do get on well with Dapol tender locos. Every one of mine runs well and I think they look good. My 9F was bought as a non runner from DCC supplies but a little bit of attention to the seating of the shaft in the loco fixed it. My Hall was bought brand new from a shop but I think it may well have been sitting in the shop for quite a while. It ran fine and then I put it away for 12 months. The next time I ran it I thought the motor was a gonner. It was very slow and then there was a wisp of smoke from the tender. After a few days I gave it another try and, after stuttering a little, she was off and running. Running very well in fact. 

 

Here is a vid of all my Dapol tender locos plus a prairie which runs nicely at slow speed. Control is analogue.

 

 

One day I will get round to adding crew to the footplates! I don't notice when viewing the layout but it looks very bad in the video.

Edited October 3, 2020 by Chris M

[andreas]

Thank you for your responses, Les and Chris. By pure coincidence I have identified the root cause of the problem. As somewhat suspected it had little to do with the locos themselves.

 

Turns out Dapol motors don't like the basic DC controller I used to run in locos before chipping them. When using a Gaugemaster controller with a bigger transformer they suddenly move on the track too. My previous set up was a Hornby P9000 transformer (19V 0.5A) plus Hornby R8250 controller and the new set up is Hornby C912 (16V, 13VA) and Gaugemaster Combi. Perhaps the basic controller simply couldn't delivery enough power for the bigger motors.

 

Thank you for sharing the video. That's excellent slow speed performance. Looks like I will have to properly clean all moving parts as per your advice. I had already cleaned the gears but didn't know how to do the same to the worm without de-assembling everything. Also, one of the Brits will need some work on the drive shaft. It looks like the tender-side connector isn't sitting straight on the motor spindle which may well explain the tender's desire to jump off the tracks.

 

 

 

[TravisM]

I must admit that I had disappointing experiences with Dapol’s Britannia’s and 9f’s, so much so I gave up on N gauge and returned to OO.  I don’t know what there like now but I found them fragile and easy to break unintentionally.

[Chris M]

47 minutes ago, jools1959 said:

I must admit that I had disappointing experiences with Dapol’s Britannia’s and 9f’s, so much so I gave up on N gauge and returned to OO.  I don’t know what there like now but I found them fragile and easy to break unintentionally.

Sorry to hear that as I love N gauge.
These are small delicate, detailed models. They inevitably  will be fragile and need to be handled with care. Never touch the valve gear and always pick them up using your thumb and a finger holding both the cab and tender.

Minitrix and early Farish are much stronger but just aren’t very good representations of the real thing. Union Mills are also robust but they have a much lower level of detail and there aren’t any models in the range with external valve gear.

Edited October 3, 2020 by Chris M

[woodenhead]

I'm back with my N, laying track this afternoon - you forget how small it all is.

 

But I wanted a bit of continuous running and longer trains - could not get that in the space I have available in OO so here I am.

 

I went to OO thinking it was an eyesight thing, but actually I think it's a lighting thing - I've seen plenty of 2mm layouts and good lighting makes all the difference.

 

Course, it doesn't help the fragility of the engines, but things were dropping of my Hornby M7 and don't get me started on all the little bits at the ends of Hornby Maunsell coaches.

Edited October 3, 2020 by woodenhead