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Morning all,

 

Big problem here and I’m worried it relates to the space available.

 

I’m trying to sort my Dad an OO gauge in his shed. We’ve got two loops and a fiddle yard up and running, with a branch at high level for a DMU.

 

The track works fine, but because it’s two loops in a shed some of the bends are tighter than I’m happy with. One Corner is quite an open bend in flexi track but the other three are second radius to give enough space for the scenic area. 

 

Some locos are really suffering. His old Coronation Class locos in particular are literally falling apart. Tyres off wheels, wheels off axles, con rods all over the place. By comparison my class 91 / class 43s breeze happily around at whatever speed I ask of them.

 

I’m wondering, is it just that the coronations are getting old, or are the curves too tight?

 

They’re able to get around them without derailing, but are the wheels getting huge lateral loads through the flanges? 

 

Locos this age don’t come with a manual telling you what the minimum radius is so I’m in the dark and open to guidance.

 

Thanks

Alan

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I always believed the old Locos were actually designed to run around the very tight first radius curves of old, it is only the past decade (or two) that manufacturers put warnings about radius two being the tightest recommended curve, due obviously to striving for better detail and tighter tolerances in the chassis I would think.

 

I would check and double check the curves on the layout with a gauge to confirm the radius, just in case.

 

Also if you have the space a small transition curve helps a lot.

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Posted (edited)

Could you widen the corner curves and include them in the scenic area?

 

The lines running through the scenic area could even be curved all the way!

 

Have you got a track plan we can see?

Edited by Harlequin
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In the big railway world, the track gets 'canted' to allow the longer wheelbase locomotives to pass around the curve. Also, the gauge (normally 4'8 1/2" gets relaxed by an extra 1/4". Assuming you  are working on 16.5mm track, one wonders if an increase to, say,  16.75 -17mm might cure a few problems. I know it's only 1/4mm, but that might make the difference between a nice ride, and 'off the road'.

Addressing the persistent problems  first is a good way to go. At least this way, you and your father are getting somewhere.

 

Best wishes,

Ian.

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RTR Coronations should be able to manage no.2 radius especially the older models (your dads' have traction tyres, which I think means tender drive, an 80s thing). If they are not recommended for this radius, you would have problems with derailments or buffer locking, but the locos should not be pulling themselves to bits in this way; tyres off wheels, wheels off axles, disintegrating motion etc.  

 

My opinion FWIW (which corresponds to the price I charge for it) is that the loco has had a hard life and could do with a bit of TLC.  You should be able to get pdf manuals for older Triang Hornby/Hornby Coronations, with tender drives, from Hornby so long as you know the correct R number to get the correct free download.  This is basically an exploded diagram which pictorially represents how the loco can be dismantled.  Bad news is you are possibly going to find difficulty in obtaining spares for any part that are worn out; Hornby, along with most current RTR companies, carry only a very small stock of spares for current models as it is cheaper and easier for them to simply replace the model with a brand new one.  This appears counter intuitive but is to do with the cost of warehousing and administering large stores of small items.  Peter's Spares and Lendon's of Cardiff are the go to for older spares, but it's turning into pot luck over time.  Lendon's will require the correct part number (X ___) from the service sheet manual pdf.

 

Tyres coming off are probably worn and stretched, and you can easily determine this by removing them and running the loco without them; this is fine so long as there are no uneven bits of track, especially on curves or pointwork, for the groove in the wheel to foul on the railhead, but will of course mean reduced haulage.  If you can't replace the tyres, there's an American thing in a tube called something Snot can't remember what OTTOMH, which is an effective substitute.  Bullfrog Snot?

 

Wheels leaving axles is much more serious, and indicative of severe wear and possibly misuse if the locos have been obtained s/h and their provenance is uncertain (a child pushing the loco to get the wheels to turn without power can break the splines holding the wheels to the axles).  And motion failure is usually down to a threaded crankpin bolt which has come loose (especially if it's persistently on the same side of the loco) and then been overtightened, resulting the thread stripping either on the crankpin bolt or the threaded hole in the crank on the wheel.  

 

If you feel competent enough, I'd strip the chassis down to components and check for wear; a deep clean can be undertaken at the same time.  If you notice wheels that come easily off their axles, you have a choice between repairing them with Araldite, ensuring that the quartering is precisely maintained, or replacing them.  In this latter case you will need to establish the axle diameter but it's almost certain to be 1/8" unless the model is Chinese made.  If it comes to this, there will be advice here.  If a crank/crankpin thread is stripped, you'll need a new set of wheels and suitable crankpins.  

 

Dismantling the chassis will produce a number of very small screws and bolts, motion bearings, and other tininess that needs to be carefully not lost.  I use a lump of BluTack to stick them in to, but Milliput or Plasticine (isn't that a geological period) will do as well.  

 

If you do not feel happy doing this work yourself, approach your local model shop, which may be able to help, or persuade someone you know is au fait with this sort of restoration work.  The manufacturers will, understandably, try to persuade you to replace the model with a new one, that their children may not starve, but this may well not be suitable for running on your no.2 curves or through turnouts of less than that radius.  IIRC the minimum recommended radius is given in the online cataglogue for Hornby Coronations, and Princesses.  

 

The limitation on sharp curvature is a result firstly of the fixed wheelbase of the loco, and a Coronation's fixed wheelbase is one of the longest, longer than an LNER pacifics.  Sideplay in the leading and trailing wheels may be used to help, but as motion and slidebars have to be cleared this is limited.  By comparison, a 91 or 43 has bogies, and fixed wheelbase is less of an issue.

 

The other limiting factor is the length of the vehicle and the amount of overthrow on curves at the ends, and 'underthrow' in the middle on long coaches such as your HST's Mk3s.  This in turn has implications for clearance of passing traffic on the adjacent track, and for the couplings and buffers.  It has been traditional since 1938 and the Hornby Dublo A4 (which could manage 13" radius) to compromise the leading and trailing wheels of 00 pacifics; HD used smaller than scale wheels, and front footsteps appeared incorrectly fixed to front bogies or not at all, so that they could swing without fouling anything on tight curves.  The current market will not accept that sort of thing, hence cutaways hidden behind cylinder blocks and flangeless trailing pony wheels.  

 

In a perfect world, you wouldn't be asking main line pacifics to go around the sorts of curves that, scaled up, would look insanely sharp even in a dockyard, but for most of us compromises of this sort are necessary.  If it's any comfort, I doubt if any contributor on this site has a main line layout with realistically curved curvature even off stage.  Even the inspirational Tony Wright, who runs ECML Pacifics with prototypical loads at scale speeds on his scale length Little Bytham layout, has sharper curves to feed his fiddle yard, or his already massive shed would need to be a good bit longer and twice as wide.

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5 hours ago, The Johnster said:

Wheels leaving axles is much more serious, and indicative of severe wear and possibly misuse if the locos have been obtained s/h and their provenance is uncertain (a child pushing the loco to get the wheels to turn without power can break the splines holding the wheels to the axles).

 

There are plastic insulating muffs between the axles and the wheels which may have deteriorated over the years particularly if the loco has experienced extremes of temperature or humidity.

 

It's not clear from the OP whether the tyres referred to are traction tyres or the metal tyres fitted to cast wheel centres on older models.

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The tender drive era Hornby wheels with separate tyres did tend to throw their tyres and the side play can cause the valve gear to tangle. The 9F had one piece wheels to get around it.  I fitted Hornby 10XX County/ Castle tyres to Hall/ B12 wheels to both stop tyres falling off and get code 75 compatibility.

I always try to avoid flexi track on less tan 2ft radius as it goes tight to gauge when curved and likes to kink at rail joints,  Conversely I cut the ties between sleepers and ease out set track to larger radius especially to lead the track into the curve, a de facto transition curve.

Most of that era Hornby had narrower back to back to help with sharp curves as well as minuscule or non existent flanges on centre wheels.  Most were actually OK on 13.5" radius Grey Triang track.  My  9F is fine on it but the tender levers itself off the track if you put a decent load behind it.  

These were basically Kids toy intended for a relatively short life.  I feel they are more life expired than suffering from excessively sharp curves.     All of my tender drive  locos of this era have been retired to the spare loco shelf or sold on eBay while a lot of the older Triang and Hornby Dublo remain in service.  The old trick of fitting Romford wheels with flangeless centre wheels has now become very expensive and the modern stuff doesn't really like less than 3rd radius.  Given your situation I would buy a Wrenn Coronation or two.

 

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Some amazing input there, thank you.

 

yes it’s the metal wheels (the 6 part of the 4-6-2) which have come loose. I suspected age initially but two second hand locos and one owned-since-new, never raced nor rallied low miler have suffered the same fate within weeks of each other.

 

Having studied the issue in more detail I’m now convinced that the problem is the transition between the boards and the bridge over the door. I’m just not talented enough to get it smooth so they’re crashing over it with jarring force.

 

last time I was up there I moved to copper clad plates and managed to tighten it up a lot. Only time will see if it helps, but in the meanwhile I have three crippled locos to sort.

 

Mr The Johnster’s post will be read a number of times this evening! 
 

In the meanwhile - photos as requested....

4826B6CD-B7AA-4677-B9EF-0B2E60621BC2.jpeg

23F92276-25AC-4AD4-8D2E-2450896002FD.jpeg

23E8A909-5F37-4435-9CB5-BD07855AE35F.jpeg

DD15C4D8-50B9-4035-8087-77EF29FAA880.jpeg

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On ‎10‎/‎08‎/‎2020 at 09:31, Realistic_build_Speed said:

...Some locos are really suffering. His old Coronation Class locos in particular are literally falling apart. Tyres off wheels, wheels off axles, con rods all over the place...

My experience of converting a couple of 1980s Hornby tender drive models to loco drive for use on an outdoor line.  The curves were very large radius (yards!) and the locos were made heavy for the traction necessary outdoors running long trains. The A3 mechanism (of probably very similar wheel construction to the Coronation) went for 8 years, and the driven wheelsets shed tyres and slipped on axles the last couple of years, requiring several fixes. The 9F lasted longer, then one day slipped two wheels on the axles and wrecked the motion comprehensively. (They had both done a lot of running and were being used in a way they were never designed for, so I wasn't overly surprised.) But the experience on the A3 in particular suggests to me that 'work them hard enough' and the wheelsets will eventually give up.

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I've had useful conversations with this company.  They told me what was fixable...and not.  I completely get the affection for old locos and desire to run them, so to me, 20 quid or so for a professional service feels worthwhile.  Others may disagree or have experience with this service.  Am sure if you sent some pictures they could do an assessment for you as well.

 

Sounds like the engine shown here is older than your fathers: http://www.Hornby-railway-trains.co.uk/Services/Tri-ang_Princess_Elizabeth_Service/Tri-ang_Princess_Elizabeth_Service.htm but gives a sense and walk through of servicing if DIY appeals.  

 

I have got a couple of older engines running again, one 1980's model better than I recall it running when new (luck?) having serviced them.. I have NOT dismantled the motion but Hornby have a double ended con rod spanner if you fancied it.

 

(noticing the incline in the pics.  Assume older engines go up OK, newer ones less so?  Working on ditching mine in a working plan when time allows so being nosey!)

 

Edited by Shanghai Diver
Fat fingered typing...
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Thanks for the link Shanghai Driver!
 

As it happens the “overpass” is for a DMU which doesn’t fit with the rest of the steam stock so it’s a fictional addition to something which is meant to be a model of Millom station in Cumbria (if the town had prospered and grown sufficiently to attract mainline stock and express passenger locos).
 

Long story short it’s very steep and not connected to the main layout, so we’ve never tried anything but the DMU on it. I can give some of the others a run and let you know...?

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On the original question: It looks like you’ve got room to widen some of the corner curves. You’ll have to re-lay the track across the lifting section so that it is still turning when it crosses the gaps. Luckily the flap seems to be wide enough to accommodate the curve. You will need to fix the tracks securely either side of the gaps so that they always line up. Most people do this by soldering the rails to something solidly fixed to the baseboards - either brass screws or copper clad PCB.

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Posted (edited)

Thanks Harlequin, and apologies for the lack of track plan. I keep meaning to draw it up but time is not on my side!


The original intent was for a third loop on the bridge though I talked him out of it as he needs the space for sidings on the scenic side. Plus the loop would have to be 1st radius given the bend so not much other than Smokey Joe would get round it.  He still occasionally mentions it though so we may yet try it before the scenery goes in.
 

I should have included the photos below as well. They show the other side of the layout. This was originally destined to be a fiddle yard but a re plan saw it become the other terminus for the DMU on the overpass and somewhere more scenic for the express to fly through at speed.
 

If I open the curves out on this side it’ll eat into the DMU’s scenic area - but that may not be such a bad thing.

488A20B2-AA38-4AE0-8075-AED57C96954E.jpeg

C6CB6B44-B8C5-4BFF-B70F-AADCFBF4D3D3.jpeg

Edited by Realistic_build_Speed
missed words
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