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Hornby Britannia traction problems


llamafish

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Hope this is the appropriate section.

 

I've had a Hornby Britannia for a few years, and ever since new, it seems to be struggling to put it's power down on to the track. The loco is kept lubricated, the track is clean etc, but at low speed, the Brit' will refuse to move, it's wheels are spinning but there's no 'oomph'. No other locos I have have this problem, is this a known Britannia issue, and is there anything I can do to help improve the traction, that doesn't involve much dismantling?

 

Any advice is much appreciated.

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The likely problem depends on whether it is a Loco drive or a tender drive Britannia.  If it is a loco drive, and the track is clean, then I would check that the track and driving wheels are not oily (unlikely that the track is oily if the other locos are OK).  You say that it is kept lubricated, but over-lubricating is very easy and the surplus oil has to go somewhere!   If it is a tender drive, then I would again check the traction tyres for oil - oily tyres will not grip!  Also, if the tyres are old, they may be slipping on the wheels - try to see if you can move them on the wheels by hand - if so, they will most likely need replacing. The tyres might also be worn or very shiny, neither of which will help traction. If none of these are appropriate or work, then you might want to try to add some weight to improve traction.  You can test this quite easily by temporarily fixing some weights (lead or old coach/wagon weights) to the loco or tender with an elastic band and then try to run it.

 

Simon

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Thanks Simon. I think it's tender drive, but it seems to do the same thing whether it's connected to the tender or not. Also, I don't think this particular model was fitted with traction tyres, although they would probably help in this case! I suspect it may well be a weight issue, as it seems OK mechanically. Certainly given me a list of things to check though, thanks once again.

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...it's wheels are spinning ...

Can you actually see the wheels spinning? Or is it the sound of the motor running that you are interpreting as spinning wheels? A dot of magic marker ink on a tender drive wheel will let you see easily if the wheels are turning. 

I think it's tender drive ...

 If so,a very common problem for the Hornby tender drive (and the old style motor bogies of the same generic design) is that the small gear on the motor shaft is loose. Hornby service retailers should have a replacement to sell you.

 

If it is loco drive - you can see the driving wheels spinning round, but it does not move - then something on the chassis is fouling the track.

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Apologies, I've just opened up the tender, it's not tender drive, the electrical connection between the loco and tender threw me. The wheels and motion definitely move, I can't see anything obvious that is fouling it. Would the little plastic brake rods foul the wheels, would it be worth trimming them ever so slightly to see if it makes any difference?

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If the driving wheels spin round, nothing is significantly fouling them.

 

You haven't put the flanged trailing truck wheels in have you, replacing the unflanged set? Cause these wouldn't fit on my examples without some filing of clearance inside the rear truck frame, and instead jammed unable to rotate in a low position which would lift the back of the loco and take most of the loco weight off the drivers - then it would barely move.

 

If not that, what happens if you try pushing the loco along? It has pretty much got to be something snagging or really badly dragging on the track, and it should either be visible, or detectable by separately testing the unpowered wheels rollability. Does the tender roll freely when tested separately? What about the front bogie if you remove that? (two screws hold the bogie bracket on).

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I've left the unflanged wheels in place. When the loco is pushed along without power (it would carry on with power, once pushed), the main driving wheels don't rotate (as they shouldn't), and only the rear wheel of the front bogie moves freely, the front was a bit sticky, upon removing it and testing it freely, it still does not turn. I've found that the end of the front coupling seems to foul the axle, preventing free movement. Once the coupling had been removed, the wheels now turned as freely as the other set on the bogie. The tender is fine. Could this be a source of the problem I wonder...?

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A jammed wheelset will be a source of drag, mechanically the front wheel is the worse of the two to have jammed on the bogie for impeding forward motion, as it 'loads up' in that direction. Give the model a try now that wheelset is free rolling to see if there is a detectable difference - there should be. (The Brit is actually one of the best in RTR OO steam for traction, as it is supplied with adequate ballast weight.)

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I've left the unflanged wheels in place. When the loco is pushed along without power (it would carry on with power, once pushed), the main driving wheels don't rotate (as they shouldn't), and only the rear wheel of the front bogie moves freely, the front was a bit sticky, upon removing it and testing it freely, it still does not turn. I've found that the end of the front coupling seems to foul the axle, preventing free movement. Once the coupling had been removed, the wheels now turned as freely as the other set on the bogie. The tender is fine. Could this be a source of the problem I wonder...?

Not had it happen with a Britannia, but It's worth checking that the loco/tender coupling is engaging properly.

 

I've had the odd occasion on Black Fives and West Countries where it doesn't 'sit' correctly causing the tender to take some of the weight of the back of the loco which then won't pull the skin off the proverbial rice pudding

 

John.

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  • 3 months later...

An update on this; I sent it to Hornby in March, who fitted a new chassis, but it seemed to be a bit tight going round corners. I've just attached the front coupling and found that the hook fouls the bufferbeam, something which didn't happen with the previous chassis. These problems suggest that the chassis is set too far back, despite being screwed in in all of the holes. I really can't afford to send it back to Hornby again, and when I tried to remove the previous chassis, one of the thin rods (AWS connector or something I seem to remember?) was attached to the body, and I was unable to remove it.

 

Can anyone suggest some advice?

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Does it pull better?

 

Regarding 'a bit tight going round corners', have you got the tender coupled to the loco on the closer hole in the drawbar? If so try it on the longer setting to see if it is any easier.

 

Also check the bogie to ensure it has full side to side freedom in the slot the bogie pivot pin runs in.

 

Out of curiousity I tried a Hornby miniature tension lock coupler in the bogie coupler pocket of one of my Brits. The top of the hook just misses the underside of the bufferbeam. With inevitable small variations in manufactured parts, I can well imagine some combinations might just foul. (For this reason, when the big tension lock coupler was standard all loco bodies were raised 2mm relative to the chassis to provide ample clearance for the much coarser parts.) Take the coupler out, and file down the top of the coupler hook slightly to give clearance would be one suggestion for a fix, alternatively use the Bachmann version which is slightly finer.

 

The flexible connection to the rear crankpin on the drivers side represents the speedometer connection. A 2.5mm over flats nut driver (Expo is the brand commonly found in model shops) will unscrew the crankpin bolt to release this. A useful tool for crankpins on both Bach and Hornby steam models.

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Hi 34theletterbetweenB&D, it does pull better, in the fact that it no longer slips, and seems to have adequate traction, but as mentioned, is now worse when going round corners, what is interesting is that even when there is no front coupling in the bogie pocket, the front wheel does not seem to move well on corners, which at first glance appears to throw the loco slightly to one side, which probably suggests why it seems to jam a bit around corners. The tender was, and has been used on the longer setting only, so I don't think that's an issue, something which can be eliminated. The bogie does have full side-to-side motion, and the whole loco is absolutely fine on straight pieces of track; the wheels on the front bogie move with no problems; no tightness or sticking etc.

 

I have substituted the coupling with a spare Dapol one I had lying around, which seems to have sorted that issue, as the end of the hook is not at a right angle, which the Hornby one was.

 

Ah yes, the speedo, of course! Thanks for the advice on which tool to look for.

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