1st Radius curves

[keithp1707821843]

Hello All

I am just finishing the plan for my second layout - I have enough space for a max width of 36 inches of baseboard - length can be up to 10 foot. Now I had planned on an end to end layout this time - but in another forum I saw comments about 1st radius curves and small locos. I only have three locos -all are 0-6-0. The posts in the other forum indicated that those locos would run fine on these curves. Has anyone had experience of using this small curves? Only I could slightly change the plan and have curves at each end to create a loop.

Thanks.

Keith

[atom3624]

Yes.

Don't!

OK, if they're older locomotives they might be able to negotiate them, but routinely, late-model 0-6-0 locomotives will have difficulty, with the shallow flanges either being forced in, to negotiate the curve, or more probably routinely climbing the rails and falling off.

Those with the brass bushes will invariably wear the bushes down rather quickly if they do stay on, permitting them to run apparently without issue, but the wafer-thin coupling rods which come with modern locomotives will start to become worn ovalling the mounting holes, or buckling the rods.

Al.

[Going Spare]

And you need to consider the length and pivoting ability of the drawbar to allow the loco to negotiate the curve without the loco and tender bodies fouling each other on the inside of the curve.

[keithp1707821843]

OK. As I thought. I will stick to my end to end idea - just wanted to check in case it was an option.

Thanks.

Keith

[96RAF]

Get yourself a few R1 curves and do a trial run.

[ntpntpntp]

If manufacturers aren't making 0-6-0s and bogie locos which can handle their own R1 curves that's poor or lazy design in my opinion.

It's similar to the problem we seem have now in the N gauge world, with some modern production British N models not able to negotiate the traditional 9" radius R1 curve (which I believe is relatively wide compared to OO's first radius?) Many modellers will have existing layouts with such curves and I'm sure they are frustrated to find the loco they would love to own cannot run on the trackwork what they already have.

The reason is usually related to the need to accommodate correctly sized wheels, bodies, and fine detail. Yet I find that with the European N models I run, most are designed to handle less than 9" radius (even large express steam locos and long diesels/electrics) because the established manufacturers' track systems go down that tight and there would be an outcry from brand-loyal fans if something's produced which cannot run on their layouts.

[Rana Temporia]

If it won’t run on 1st radius curves it’s no use to me. I live in a small house and by necessity use them.Happily all my Triang, early Hornby and continental locos don’t have an issue.

My Jouef 2-10-0 runs round them very happily with all wheels flanged, the Triang Hornby 9F I have also runs round them happily with the prototypical unflagged centre wheels. Wrenn 8F, no problem. The Jouef/Playcraft R1 Curves were 12.75” radius and most of my Triang stock will run on them. I have a Bachmann 10000 that also seems Ok on R1. You won’t know until you try!

[keithp1707821843]

Oh ok - a few alternative views then! I thunk I will try out the 3 locos i have and see how I get on. Can I just ask what you mean when you say 'flanged wheels?'. Thank you.

[LTSR_NSE]

@keith - the wheel flange is the tapering rim which keeps the loco on the track (it looks a little like a pizza cutter.) On newer models (except 9F) all wheels are flanged - whereas on older models the centre wheels had flat rims (to help negotiate tighter radius curves.)

The 9F still has flat rims on the centre wheels, because the real 9F had them!

[What About The Bee]

Flange-less wheels were a Robert Stephenson invention! The main worry with Planet, LMR 9, was the lateral force that flanged wheels placed on crank axles.

Patentee, LMR 33, was a 2-2-2. The center driving wheels were, as usual, on cranked axles. To eliminate the lateral forces created on cranked axles, Stephenson eliminated the flange. No flange means no lateral force. This was explicitly stated by Stephenson as a patent criteria. The front and rear axles contained flanged wheels, per the patent, and the driving wheels with the crank axle did not.

Bee

[96RAF]

If manufacturers aren't making 0-6-0s and bogie locos which can handle their own R1 curves that's poor or lazy design in my opinion.

It's similar to the problem we seem have now in the N gauge world, with some modern production British N models not able to negotiate the traditional 9" radius R1 curve (which I believe is relatively wide compared to OO's first radius?) Many modellers will have existing layouts with such curves and I'm sure they are frustrated to find the loco they would love to own cannot run on the trackwork what they already have.

The reason is usually related to the need to accommodate correctly sized wheels, bodies, and fine detail. Yet I find that with the European N models I run, most are designed to handle less than 9" radius (even large express steam locos and long diesels/electrics) because the established manufacturers' track systems go down that tight and there would be an outcry from brand-loyal fans if something's produced which cannot run on their layouts.

 

 

That is akin to saying full size main-line loco manufacturers should design their locos to run on tight factory and dockyard lines, suited only to 4 wheelers. Bear in mind our largest radius set-track doesn’t come anywhere near the tightest tracks in the real world, so it is all nonsense in the great scheme of things. You only have to look at the gap on any curved platform in a station versus the yawning chasm seen on our models to compare effect.

[Aussie Fred]

Interestingly, when I moved my layout out to the garage, I found I did not have enough room for the third (inside) track with only 70cm diam to spare. Too small for 1st radius so I had a go with flexible track and laid it at the 70cm. I remember someone doing an experiment with sharp curves and he had it down to ridiculous radius and still got some locos around it. I managed to get my Oxford 0-6-0 to go round it but when I put the Hornby LSWR 4 wheel coaches on behind they regularly derailed.

My Brighton Belle couldn't get around it, only because the bogies have a limit on how far it will swing.

SO, now in the process of expanding that section to allow for 1st radius, or hopefully 2nd radius, as 1st may not be enough for the Brighton Bell or Southern Railway 2BIL.

[keithp1707821843]

Ok thanks for the replies - very helpful. I think my best bet is to set up a small test track and try the three locos and coaches. The coaches/ wagons are all small as well, I didnt see the point in having large coaches on the 1st layout - it just looked silly! So everything is small! Anyhow I will try it and post the results here for other people - in case anyone is interested.

Cheers.

Keith

[RDS]

On part of my layout, I have 4 concentric ovals, in 1st, 2nd, 3rd and 4th Radius on an 8' x 4' board. I can run Class 05, Class 08, Class 15, Class 20, Class 37, Class 42, Class 47, Class 52, Class 58, Class 66, Class 70, Class 108 and Class 128 Diesels.

Also I can run Flying Scotsman, Royal Scot and another Steam Loco LMS 2-6-4.

In fact the only Loco I have not been able to run was a Duchess of Gloucester, which I sold.

All of these run without any issues at all on my layout. I must emphasise though that I treat it as a Railway Layout, not a Scalextric Race circuit and my track is perfectly flat.

I have never been able to understand the '2nd Radius and up only' caveat.

[threelink]

I have successfully run small locos (0-6-0) and even a Lima Class 25 round a seven inch radius curve (but had to file a small cut into the Lima chassis to prevent the gears from binding). Bogie stock ran fine, short wheel base 4 wheelers ditto, but longer wheelbase 4 wheelers did not - the tension lock coupling hooks came up tight on the curve and threw the wagons off the track. The solution was to source older D link tension locks - the hook is fractionally longer than the hook on more recent D links. I strongly recommend experimenting to see what you can get away with. You might be pleasantly surprised. Good luck.

[atom3624]

May not be important to some, but the point I was making above was that whilst some may well negotiate some very small radius curves, it will come at a price, which is that it will probably accelerate the wear rate of the chassis.

Al.

[keithp1707821843]

May not be important to some, but the point I was making above was that whilst some may well negotiate some very small radius curves, it will come at a price, which is that it will probably accelerate the wear rate of the chassis.

Al.

Ok thanks. I do not use the locos as much as other people - I suspect - so that may not be an issue for me. I think I was more concerned about the derailing - etc, but your views are important to me. I am going o set up a small oval with the curves and two straight pieces and try all three locos plus my coaches - which are the small ones and some of the wagons. Hopefully that will let me see if it would work.

Thanks.

 

 

[Rana Temporia]

What might be of interest is that the Manchester Metrolink is designed to go round curves that are a scale 15” or Hornby first radius.

Also, the 9F and some early locos aren’t the only ones with flangeless wheels, some short wheelbase industrial locos also has flangeless central wheels due to the extremely tight curves they worked on in steelworks and the like.

Prototype for everything!

[keithp1707821843]

Thought people may be interested in this -

I will still be testing my locos first!

[atom3624]

The track, layout and rolling stock are yours - you own them and do what you like - simples.

That you say you'll not run for extended periods is obviously a bonus and will assist in their longevity.

Al.

[Aussie Fred]

As advised above, I have pulled a quarter of my track up and re-layed the inner track to 2nd radius. Now running my Class 55 Deltic, it just makes it round that curve BUT in making the adjustment, I find I have left a small gap 1.77mm in the track further around, which I didn't notice at the time. It is enough to cause derailments, regardless of speed. Is there any way to fix it without taking it all apart again. The gap is in both rails. I was wondering if soldering across the gap and filing it down to match the track would fix it? Has anyone tried that?

[atom3624]

Hi Aussie Fred, is this 'seasonal' / is it close to cold drafts / aircon?

I doubt 10'C change will make much of a difference, but it might.

How well 'located' is the track? The rails cannot be worked in slightly to close the gap even 0.7mm perhaps?

Al.

[Aussie Fred]

No, it was just a pure oversight when I finally nailed the track down. It is at the other end of the curve I corrected and hadn't been 'seated' properly into place. There is about 2 metres of straight and the full curve I would have to pull up and push the offending rails together and then replace them. The worst part is I ran the loco around the circuit without any hitch before I nailed and glued it down, but must have pulled it apart that fraction while fixing it permanently.

[atom3624]

Pity.

Others will advise if there's 'a fix'.

Al.

[ntpntpntp]

@Aussie fred Can you slide the rail joiners to one side, insert a tiny length of cut rail into the gap, and slide the joiners back across? That would be the best fix if you can't lift and move the track. Normally it's possible to do this with flexi track (even if you have to temporarily remove a sleeper to expose enough rail) but might be tricky with sectional track if the joiners are fixed.

Alternatively I guess you're looking at some sort of fill, maybe with solder. That won't allow any movement for expansion with temperature variation though.