Tender driven Coronation class stutter

[AndyThomas]

Hi everybody.  Wondered if anyone could advise on a stop / start / stutter problem I have with a tender driven Coronation class as on service sheet 162.  The tender is absolutely fine and runs great but when it is attached to the engine it is intermittent.  I gather that the negative feed is picked up by the unbushed wheels on the loco and have made sure all is clean but still getting a dodgy connection somewhere.  On the basis that there are 3 wheels picking up the negative and they cant all be dodgy I guess the bad connection must be further back towards the coupler and pony and the screws that hold the pony etc in place.  Anyone have any ideas what may be causing this. One question I do have is that there is a small copper spring washer part S2315.  Does this go under the screw head or under the pony arm.  I think it may have been in the wrong place when I aquired the train but dont have another one to refer to and the service sheet does not show clearly.  Many thanks.   Andy

[ColinB]

It might be the Loco to tender connection. If it is the same as a lot of my Duchess class locos then it is a pin going into a sprung loaded hole in the tender. As the loco moves it loses connection. On mine I replaced it with a wire connection.

[Going Spare]

As Colin says, the loco drawbars are often a suspect connection, but it may be necessary to trace the electrical path from the driving wheels onwards through to the tender.  All interfaces need to be clean and firm, and unless you are using a conductive oil, free of insulating substances such as oil and dirt: between axles and chassis block, pony truck and fixing screw (washer sits between pony truck and chassis block), drawbar and fixing screw, drawbar contact arms and tender pin.  An unlikely cause but also check that no strands of the cable connecting the tender pin to the motor brush arm are touching the front weight. 

[GWR 14xx Tank]

I have a similar problem on my Tender Driven Golden Eagle, the connection makes the locomotive jittery and it stops and starts even when the track and wheels are clean.

 

Another problem I have noticed is that the front wheels of the tender seem to be partially lifted from the track, thus incurring a loss of pulling power.

 

I think I will take @ColinB's suggestion and permanently wire the tender and locomotive together.

 

I have had several Tender Drive locomotives in the past and all have had similar problems to these. 

 

I strongly dislike the Drawbar / Pin connections on tender driven locomotives.

[atom3624]

This brought back memories!!

 

I had a KG 6 when I was a teenager, a fair while ago ... and I rememer the very same issue occasionally - very same reason as well - drawbar connection.

 

After all was cleaned and set up correctly, it was an excellent, fast and powerful runner.

 

Al.

[GWR 14xx Tank]

I hold my hands up - I had a moment of rage in my previous post!

 

No need to hardwire the tender to locomotive anymore for me, just a simple bending of the fingers and drawbar fixed the problem right away.

 

Back to running how it used to when I first got it!   😀

[ColinB]

On my Duchess and A4 tender driven locos, I converted them to DCC, so I used the excuse to put the DCC socket in the loco and connect the loco to tender with the Hornby 4 way lead and socket, putting the 4 pin socket in the loco as it is easier to find something to screw it to. I also added pickups to both sides of loco wheels. The result is that they run better than they ever did.

[81F]

 Hi Andy, I too have had similar problems with my tender drives particulartly those stored for many years and cleaning the draw-bar pickups and brass spike on the tender usually worked. However, corrosion on the steel axels might stop current getting through to the chassis block.

 

If your axels run in brass bearings held in place by a plastic keeper plate, cleaning is relatively easy. Just drop the wheels, push each bearing to one end of the axels and clean the bearing surfaces on both sides. If there is no keeper plate that allows you to drop the wheels sets try towing the loco for some time in the hope that any corrosion ears away.

 

[AndyThomas]

I have a similar problem on my Tender Driven Golden Eagle, the connection makes the locomotive jittery and it stops and starts even when the track and wheels are clean.

 

Another problem I have noticed is that the front wheels of the tender seem to be partially lifted from the track, thus incurring a loss of pulling power.

 

I think I will take @ColinB's suggestion and permanently wire the tender and locomotive together.

 

I have had several Tender Drive locomotives in the past and all have had similar problems to these. 

 

I strongly dislike the Drawbar / Pin connections on tender driven locomotives.

 

 

Have seen a video on YouTube with the Scottish guy that might cover this and if the front wheels of tender are off the track a simple bend down of the hook up bit the tender fits into will sort it out

[Going Spare]

Before you resort to drawbar bending, check that the tender pin has passed fully down through it and that the drive unit is seated correctly in the tender chassis frame.

Erratic running can be caused by a poor electrical path so check the cleanliness of the tender pin and the drawbar contacts plus the areas where the drawbar and pony truck screws make contact with the pony truck frame and the chassis block, also the coil springs in the drawbar (if fitted) and the one through which the pony truck screw passes as these are all important in passing electricity to the motor. Any dirt or congealed oil in the loco driving wheel axle journals can also act as intermittent insulants.

[threelink]

Hi Andy T and everyone. Great to have the forum back. I had a similar problem on a Hornby 9Fand yes, it was the loco/tender drawbar connection. It was a bit mashed and defied all attempts to achieve a remedy by adjustment of the contacts. Rather than faff about further I strung a bit of trimmed down biro spring between the loco and tender drawbar contacts The problem went away never to return.