Hornby Adams Radial Problems.

[Bufferstop]

If the manufacturer doesn't fit traction tyres, forget them. They are a complication that anything with a problematic wheelbase can do without! The front bogie is ultimately restricted by the outside cylinders. If it leads the loco into a curve which is too tight the driving wheels will end up askew of the track centre line, and the trailing axle may run out of sideplay, so some of the wheels will have their flanges grinding against the railhead.
The possible cures are; as much side to side movement as can be obtained for the bogie, its wheelsets and the trailing axle; Then as much weight upon the driving axles as can be added. The driving wheel's back to back dimension needs to be the minimum your trackwork will permit, as the flange contact will be reduced if the driving axles are not truly aligned with the track.
A problem found on many 2nd radius layouts is that the radius is an average there being tight spots particularly in points and at rail joints especially if laid in flexi (or settrack that's not correctly joined). Older versions of Triang designed Pacifics cheated by mounting the trailing axle in a pony truck and leaving the centre drivers clear of the rail, so being a virtual 4-4-2, isn't this where we came in? They went round first radius curves if you allowed a ridiculous gap between loco and tender, and the solid lump of Mazak which served as a chassis ensured plenty of weight on the drivers.

[waz]

Hi Chaps !
Thank you all for your input.
@ Mike Parks. Yes, I think that is one of the main reasons for the problem. I had a good look yesterday and I filed a little off the rear bogie truck to lower it. No dice. Also @Dad-1. There is no room for weights in the smoke box. That is taken up with a cast cylindrical weight which is part of the body.Obviously Hornby had the same problems during the design.
@Bufferstop, Bigmet,SRman. Thank you all for your input and taking time out to try to help.
I think it's time to call it a day on the problem. I've been a member of the forum for 17 years and you have all helped me at some time or another. I'm 77 now and hope to make it a bit further down the tracks. I will continue with my evaluation of the problem and if I come up with anything startling I will let you know. Thank you all once again.
My Best Regards.
BILL.

[mattmay05]

Both Radial's by Oxford and Hornby respectively have the same issues..

Their haulage was never great... but Mr Trains certainly demonstrates not just why they shouldn't be run on carpets, but also what the Radial doesn't like.... if there is a small dip in the track the driving wheels will be left spinning in the air, or loose traction momentarily.

The chassis design for both is poor, the Early oxfords the bogie got stuck behind the bufferbeam... which they fixed later on... but still shares the same issue, Hornby's is the same the rear pony truck doesn't have any movement upwards, so a small dip it grounds out.

I have completely rebuilt the back end of my Hornby version and 3D printed a new back end for the radial axle, basically copying Bachmanns Radial axle off their E4... since then I have had no problems it took a while to get the balance right but it's much happier.
For me the Hornby one detail and look is superior to Oxfords, which is a bit of a mish mash of parts, It had a lot of parts during its life, 4 domes, 2/3 chimneys, different boilers, different cylinders, Oxfords just isn't quite right.

[manna]

G'Day Gents

Bit late to the party, try removing the front bogie, run it as a 0-4-2, it will a least allow you to see if it's lifting the coupled wheels off the track.

manna

[bulleidboy]

I'm coming very very late to the party (is it still going on? ). My Hornby (R3333) 30584 Adams Radial bought in 2016, was one of the models with the incorrectly wired decoder socket - I'm told Hornby were aware of this but kept quiet! I managed to correct the wiring, but the loco is an absolute pig. One thing I have found and has not been mentioned, is that it runs perfectly with the body off. The loco is fitted with a TCS DP2X-UK decoder, and on the rolling road, with the body off, I can get the slow running down to 2rpm., and in this condition (body off) it will run perfectly around the layout all day. However, with the body on, there is a major transformation, jerky running or not running at all. There is a small stud on the top of the rear bogie which fits into a slot in the bodywork under the coal bunker, it is very easy to put the loco on the track with this stud out of position - the loco will virtually, with a gently push, free wheel around the layout, due to the driving wheels being lifted above the track. There does not appear to be anything on the bodywork that is fouling the wheels - I have had this loco apart on many occasions, and have about given up. It now sits on show, on an old siding not connected to the layout.

[Bigmet]

The running problem you are describing is a classic DCC related job. DCC decoders are intolerant of power supply interruption: they run jerkily, and on occasion not all, because there's no power reaching the decoder, interrupted temporarily or permanently.

Yet the mechanism runs well with the body off, thus there is no motor, drive train or decoder fault.

The clue to cause is

...There is a small stud on the top of the rear bogie which fits into a slot in the bodywork under the coal bunker, it is very easy to put the loco on the track with this stud out of position - the loco will virtually, with a gently push, free wheel around the layout, due to the driving wheels being lifted above the track...

The 'free wheeling' with the body on will deprive the most reliable pick up wheels - which are on the two driven wheels - of any chance of reliable pick up.

I would put money on the root cause being the loco body interfering with either one or both the carrying wheel mountings.

For the rear truck, on which you have already identified a problem, generously enlarge the slot in the body work in all dimensions, so the 'stud' cannot find any way to foul.
If that fixes the problem, you are good. But if not, then the front bogie:
Do whatever is necessary to increase its upward movement freedom. This may require either or both of the chassis block or body work having some material filed off the underside, so that whatever linkage joins the bogie to the rest of the loco is less constrained.

Small four coupled tank locos with carrying wheels both ends were notoriously difficult to make run well, back in the day when kit or scratch building was the only way to have one. The additional problem with all metal kits was that the carrying wheel flanges were often 0.5mm or less below the footplate underside. Been there, got that T shirt...

[bulleidboy]

Many thanks for your suggestions - I will give them a try. May be a while, but I will report back.

[Dad-1]

Different loco, but a M7, another with lack of traction and tight clearances everywhere
gave me the same problem.
What I found in the end was that when the body was on it somehow nipped the motor
fittings and allowed one of the drivers to contact one of the motor terminals. This caused
all sorts of running problems that of course vanished when the body was off !! The wheel
wasn't fully true so contact was rather random.

What you need are crazy ideas for mystery solving !

Geoff T.

[Bigmet]

...What you need are crazy ideas for mystery solving !...

I would phrase that a different way. Be open to investigating any potential cause which is consistent with the available evidence. Because sometimes the logistics manager is making 'cost savings' on the transport budget by shipping shock sensitive items in the enpty return trips of 80 ton quarry trucks. (And I was told I was crazy for even venturing to suggest such a thing.)

[Dad-1]

Watch it Bigmet,

This old bird was a logistics manager and I did save money.
Luckily we didn't have delicate, or time critical goods to deal with.

Geoff T.

[Bigmet]

No particular bias on my part, over the years I found just about every occupation, accountants to yard dispatch, as the source of the 'mystery' problem. It was relatively rare though to get one as blindingly obvious as the example: arrived on site in the land of 'Alles immer in ordnung', diagnosed cause within 10 minutes, proved inside the hour thanks to a fast car to the closest offload point. My all-time favourites: electronics assembly operatives using a newly introduced and very fashionable hairspray, which led to development of a very subtle product defect months later, and a metal supplier that had accidentally and undetectably altered their casting process, with occasional catastrophic results in subsequent machining of the output.