Strange problem with Airfix Prairie Tank

[Castle-Man]

I have a strange issue with an Airfix Prairie Tank.  I have it running very well and is not too noisy.  Runs Ok in both directions and slow and fast EXCEPT!  If run arond a layout that is mainly curves then after running for a while it will slowly come to a halt after a few minutes.  

It appears to stop because something has tripped the controller as I have to switch the direction off and leave it for a while and then it will start again when I switch the direction back on.  If I do not leave it long enough it will only run for a short distance before stopping.  If I leave it long enough then it will run again for a few minutes before stopping.

I have tried different power packs and Power units with the same result.  I have also tried other trains and this does not happen with them.

The test today was with 8 2nd curves 2  half length straights.  I was using a R965 which I assume would be a similar era and the loco would not draw too much power.  Other trains that I have and do not exhibit this are a Hornby Albert Hall a County of Worcester and a 0-6-0 tank loco.

Can anyone think of any possible reason.  I can only think  that something is shorting somewhere when the loco continues to go around corners.  The contacts seem ok on all 6 drive wheels although  I suppose the lateral movement could cause them to move but they seem pretty well sprung against the wheels.

Causing much grief for 'the little grey cells,'

[Howbi]

The R965 controller is very easily overloaded by older motors as I very soon found out trying to run my Hornby Dublo 3 rail stuff..........when the loco was running round the curves, the extra resistance from the curve drawing more current may have been enough to cause the thermal cut-out to get hotter and then shut down........consider a better controller..........HB

[Castle-Man]

Thanks I did wonder.  Trouble is it is a lot to send if that does not solve it.  Especially as I have 3 and otherwise they work fine including the AC aux feed for my points.

What have you in mind as I thought that was even more of an issue with modern controllers designed for locos with a lower power demand?

There seem to be Guagemaster Model D for just over the £50 mark second hand.  Years ago I used to like H & M controllers e.g. Duett but have heard that there can then be problems with modern trains? 

[The Doc]

Castle-Man,

The H&M Duette works fine with modern trains - just make sure you set the slide switch to High Resistance.  I had an old Wrenn 2-6-4 tank that ground to a halt after a few laps with any controller except the Duette.  I never found out what the problem was, but the Duette is indestructible.  Mine must be at least 45 years old and has never given me a problem - it works fine with all the Hornby models I have bought, old and new.  Gaugemaster are also good, and I use their feedback model that works well with tight curves, inclines, and slow speed control.  The Hornby "trainset"controllers give reasonable control, but are not suitable for older motors, and I would include the Airfix open frame motor in that category.

[Castle-Man]

What about a HM Clipper Controller with an attached H&M DC Controller?

You also say Hgh resistance for modern trains.  Is that also for older models?  If not what do you class as modern?

[The Doc]

 The clipper + H&M DC controller should be fine.  The Clipper was just a single track version of the Duette.  I would only use the Low Resistance setting on certain much older models (Pre-1980s) that have XO4 style open frame motors; it just gives slightly more power to those motors.  Even so, the High resistance setting gives slightly smoother starting and stopping with those older motors, just a lower top speed.  The Airfix Prairie would run better on the High resistance setting.  I used to own one and that's what I used.

I would class most locos from 1980 onwards as modern in the sense that the motors ("Ringfield" and modern can motors) tend to draw far less current.  Having said that, I'm surprised that your Albert Hall doesn't also cause problems with the Hornby controller you are using.  The Airfix Prairie may be drawing a lot more current as it goes around bends - a bend can cause just as much physical resistance as a moderate incline.

[NFSCARBON]

It's possible the magnet in the motor is getting weak, not enough to visibly affect running, but it may be increasing current draw. 

[Castle-Man]

Thanks for all replies.  Maybe a service and re-mag would be woth looking at sometime but dont want to spend a fortune and be withouth for too long.

May try a H&M and see for a while.  Although they seem to fetch quite a price almost same as H&M 2000 and Guagemaster second hand. 

[Blue Pullman]

I too have one of these Prairies which has been in storage for years and didn't want to work so I stripped it down and serviced it with the help of a You Tube video. My reason for replying is that I had a great deal of difficulty getting the motion back in correctly and for it to run smoothly.  I'm wondering if yours is running slightly out of true and sticking on the curves?  Mine was ever so slightly bent and the rods going into the cylinders were sticking. Actually it's still not good after hours of fiddling but I'll get back to it in the Autumn 

Roger

[Castle-Man]

Thanks Roger.

I think it is related to the extra load from curves however recently instead of the Hornby Controller I tried a H&M Clipper.   Running for quite a while on 2nd curves and even 1st curves as a test things kept going.  On 1st I noticed the occasional slow down but the extra power of the H&M kept things going whereas the Hornby R965 would trip out.

In fact I did notice anyway that a number of locos slow a little when turning into the curve even with 2nd.  Suppose that is what feedback controllers are designed for. 

I also know exactly what you mean about re-fitting the cylinders! 

 

 

[Blue Pullman]

Hi Castle Man

you are probably right but I thought it worth mentioning. I'm just retired and have got my railway out of storage after 25+ years. I have 1st 2nd & 3rd radius curves to use as it happens I am not using steam it will all go and the railway will be based on my make believe scenario of a dmu and blue Pullman heritage railway therefore hopefully I have no radius issues as most bogies go round most curves 

Roger

[Rana Temporia]

I got one of Hesse when they first came out. Check the back to back of the wheels as mine were very loose and needed to be regularly re-set especially on the pony trucks. This could cause excessive drag on the curves. Of all my locos I had then this was easily the most powerful and could drag two old Grafar metal kit coaches with no problems. So it could be current draw. Good luck with a solution. 

[Castle-Man]

Rana Temporia

 

Sorry to be thick but what do you mean by, "Check the back to back of the wheels as mine were very loose and needed to be regularly re-set especially on the pony trucks." 

[Fishmanoz]

Distance between wheel flanges.