Dapol Locos on 2ft Radius Curves?

[BRTrainz]

Hi, was wondering if any one has tried running Dapol locos on on a 2ft or similar radius?

I realise this is far from an ideal radius (to say the least) in finescale O but larger is not really an option for me right now if I want a loop.

[Hal Nail]

 

[F-UnitMad]

From my own tests - 0-6-0 Pannier Tank - not a chance in hell. There isn't enough sideplay in the central axle. 3ft is the minimum and as I wrote before as linked to above, even that is pushing it for UK stuff.

 

The only O Gauge that will take 2ft radius curves is the 3-rail stuff by Ace & Darstead. They have a certain charm & atmosphere all their own, but Finescale they are not.

[Simond]

Ixion Fowler.  I’ve not tried it, but I’d expect it to work, as any ultra-small 0-4-0.  You would likely want extended coupling links, and you might well get buffer lock when pushing, despite the large heads typical of such locos.  You could perhaps shunt one 4W wagon at a time.

 

here’s a bit of reality, Wallasey side of the Birkenhead docks.  Real radius maybe 125 feet.  Scales out at about 2’10”.

 

I’d say 2’ won’t work, and even if it “sort-of” does, it’s unlikely to be satisfying.

 

[goldfish]

18 hours ago, BRTrainz said:

Hi, was wondering if any one has tried running Dapol locos on on a 2ft or similar radius?

I realise this is far from an ideal radius (to say the least) in finescale O but larger is not really an option for me right now if I want a loop.

 

It might be possible to run a Dapol Sentinel on 2ft curves, I haven't tried it but I have a fine scale Walsworth Models Sentinel Shunter that runs faultlessly though 2ft curves and points.

 

The other alternative are ETS loco that are designed for 2ft radius curves, even their Austerity 2-8-0 copes with 2ft curves. They even do a range of 2ftb curved setrack. As a bonus their 1.5mm flanged wheels will run through Peco points with no problem and without wheel drop. I should emphasise that the 2mm and 2.5mm flanged wheels fitted to 2 - 3 rail switchable locos are not compatible with ETS or Peco points.

 

The big problem you face is couplings. While it is possible to pull finescale stock through 2ft curves, propelling them is a different matter. The best solution that I have come up with is to replace the 3-link Couplings with Sprung Drawbar Drop Link Couplings.

 

While it is possible, it requires a great deal of compromise, but if are more interested in operation rather than authenticity it is an option.

 

Edited April 10, 2022 by goldfish

[BRTrainz]

Thanks all.

Was really hoping I could get away with an 08 or terrier (expected the Pannier was too long) but oh well.

Think I'll order a sentinel and see how it goes.

Been looking at some of ETS' small locos (the Austerity and S160 are tempting but WAY out of my budget for a single loco) and will probably go for one sooner or later.

Already have a few used kit built wagons and an Atlas/Roco 2ft radius point that I've pushed them through, so know what I'm dealing with when it comes to couplings and buffer lock, etc.

[MarcD]

I would put my money on a sentinel going round the curve on its own but I think you are going to struggle with couplings and buffer lock. My Flippem couplings only go down to 3ft and that is pushing them to the limit. 

I would advise thinking again at the round d round if it was me.

 

Marc

[F-UnitMad]

6 hours ago, MarcD said:

I would put my money on a sentinel going round the curve on its own but I think you are going to struggle with couplings and buffer lock. 

One of my friends who owns a Dapol Sentinel said exactly the same thing yesterday when I discussed this Thread with him. 

This was one of the photos I took of my UK O wagons on the 3ft curves of my US O layout.

3-links are already stretched to the limit, the buffers aren't compressed but the gap between the far ones is in contrast to the near ones which are touching.

With the Dapol tanker coupled to the Minerva Pannier, it's another story.

Both near buffers are pushed in, and the 3-links are pulling the Minerva hook out from the buffer beam. I think the spring on the Minerva hook is softer than the Dapol one.

This, remember, is 3ft radius. 

[goldfish]

The original question was asked by someone in North America where small radius curves are more the norm than in UK.

 

Buffer lock is easily overcome by changing the couplings, this Walsworth Sentinel and Dapol wagons fitted with drop link couplings are perfectly at home on my shunting plank with 2' points.

 

 

They will even go through 18" reverse curves. Longer wheelbases are possible, but if there is contact between buffers they need to be solid buffers, as on these 4-wheel coaches.

Edited April 14, 2022 by goldfish

[Matloughe]

Those are some really good examples Goldfish, what track are you using?

Those coaches look good as well.

 

Kind Regards,

Gary

 

[goldfish]

Just now, Matloughe said:

Those are some really good examples Goldfish, what track are you using?

Those coaches look good as well.

 

The track is ETS, with code 175 steel rail, and hence not compatible with Peco.

 

The coaches are cobbled together by me from resin coach parts by 422ModelMaking on an ETS coach chassis. They are pretty much the limit for rigid vehicles on 2' curves, but manage 2' reverse curves quite happily.

 

The couplings are a direct replacement for 3-link couplings, and while not commercially available can be obtained by special order from Walsall  Model Industries.

 

[BRTrainz]

I've purchased a Dapol sentinel.

My intention is to test with wagons on the 2ft radius track I've already got and if it doesn't work out I'll go with a point to point layout.

Will likely go with Peco R2 if it ends up being point to point.

Want to avoid drop links as realistic link couplings was part of what attracted me to O gauge.

Edited April 14, 2022 by BRTrainz

[Nearholmer]

The issue about "getting round corners" relates primarily to fixed wheelbase, so if my coarse-flanged Sentinel will get round 2ft, which it does, 18" in fact, a fine-flanged one will too. Any loco with a similarly short WB ditto.

 

The problem comes with six-wheel locos, because if there is a lack of play on the centre axle, and the centre wheels have flanges (the old trick was to have none), then the 'effectively fixed' wheelbase becomes too long for super-tight corners. I did have a Dapol 08, which I bought with a view to "coarse-scaling" it, but found that there was barely any play on the centre axle, and it would have involved a lot of work to create sufficient play, so I sold it.

 

Goldfish has illustrated very well one solution to the buffer-locking problem. Another is "the Leeds method", named after the now mostly forgotten Leeds Model Company, which is to use very wide buffers, together with three-link couplings with fairly generous links and a soft spring. 
 

Here is an ancient LMC wagon, which works fine on 2ft radius in a rake of others with wide buffers.

 

 

 

Edited April 14, 2022 by Nearholmer

[F-UnitMad]

1 hour ago, Nearholmer said:

The problem comes with six-wheel locos, because if there is a lack of play on the centre axle, and the centre wheels have flanges (the old trick was to have none), then the 'effectively fixed' wheelbase becomes too long for super-tight corners. I did have a Dapol 08, which I bought with a view to "coarse-scaling" it, but found that there was barely any play on the centre axle, and it would have involved a lot of work to create sufficient play, so I sold it.

My old Atlas/Roco Plymouth switchers have 'blind'(flangeless) wheels on the centre axle. I have acquired several sets of spare flanged wheelsets, so I thought I'd be clever & replace them with flanged wheelsets.

It was a disaster!! Even on curves of 3ft min. radius they started binding, and on some of my 'bad' track (intentionally so) they struggled too. Swapped them back to blind centre wheelsets and no more issues.!!

[goldfish]

19 hours ago, BRTrainz said:

Want to avoid drop links as realistic link couplings was part of what attracted me to O gauge.

 

I understand your sentiment, but failing eyesight and reduced manual dexterity make 3-link couplings a complete nightmare for me.

 

One thing I did find useful with the Dapol wagons was to replace the 3-link couplings with Dapol Screw Link Couplers. They are a tad longer and give more clearance. If you mobilise the joints with a couple of drops of glue you essentially create a drop link which is much easier to couple and uncouple.

[goldfish]

16 hours ago, Nearholmer said:

The problem comes with six-wheel locos, because if there is a lack of play on the centre axle, and the centre wheels have flanges (the old trick was to have none), then the 'effectively fixed' wheelbase becomes too long for super-tight corners. I did have a Dapol 08, which I bought with a view to "coarse-scaling" it, but found that there was barely any play on the centre axle, and it would have involved a lot of work to create sufficient play, so I sold it.

 

For six-wheel locos the best way to get them around tight curves is to give the centre axle the normal amount of play, and to give the outer axles a greater degree of freedom. 2-2.5mm play on the outer axles seems about right for most 0-6-0 locos on 2' radius.

 

If the clearances are correct all flanged wheels are perfectly possible. ETS Austerity 2-8-0 on a 2' curve.

 

 

It is not very pretty, but it does work. It will also go through the reverse curves on my shunting plank with ease.

[F-UnitMad]

6 hours ago, goldfish said:

It is not very pretty, but it does work.

And there's the rub. Yes you can get O gauge to take 2ft radius curves, but 'finescale' it ain't. The trick is to grasp the nettle and accept 'coarse' O for what it is, and make the most of the charm & atmosphere it can possess.

See the works of Mr Nearholmer on this Forum for details.

 

Edited April 15, 2022 by F-UnitMad

[goldfish]

2 hours ago, F-UnitMad said:

And there's the rub. Yes you can get O gauge to take 2ft radius curves, but 'finescale' it ain't. The trick is to grasp the nettle and accept 'coarse' O for what it is, and make the most of the charm & atmosphere it can possess.

 

There are two aspects to making any working model. Building a reasonably accurate representation of whatever you are modelling, and model engineering to make the model function in the environment for which it is designed to work in. The only real difference between 'Coarse Scale' and Fine Scale' is the wheels, there is no physical reason why fine scale cannot be engineered to work on tight curves, it just needs a different approach.

 

It also depends on what you mean by finescale. The ETS Austerity runs through Peco Streamline and Setrack points without a problem, an argument could be made that it is finescale.

Edited April 15, 2022 by goldfish

[friscopete]

The Dapol B4 might  when it comes out .My 00 version does 6 inch 00 curves very well .

[Nearholmer]

2 hours ago, goldfish said:

there is no physical reason why fine scale cannot be engineered to work on tight curves, it just needs a different approach.

Which is true in large measure because, whisper it quietly, GOG ‘fine’ isn’t actually very fine, just finer than ‘coarse’. If you go to S7 things do get pretty close to being miniaturised reality, so trains won’t run round curves tighter than their real counterparts.

[F-UnitMad]

5 hours ago, goldfish said:

 

It also depends on what you mean by finescale.

Agree with you there!! That is very much a can of worms!!

[goldfish]

12 hours ago, Nearholmer said:

Which is true in large measure because, whisper it quietly, GOG ‘fine’ isn’t actually very fine, just finer than ‘coarse’. If you go to S7 things do get pretty close to being miniaturised reality, so trains won’t run round curves tighter than their real counterparts.

 

From a model engineering point of view there is little difference between finescale and S7, it is all a question of getting the necessary clearances. If you set the B-B on S7 wheels to 29mm they run perfectly fine on 2' radius curves. The wheel drop over points is terrible of course. A conversion from fine scale to S7 increases the B-B from 29mm to 31.2mm so there is plenty of room for extra play on the axles. Somehow I do not think the S7 brigade would approve.

[F-UnitMad]

It still depends on what you want to run on sharp curves. Going back to my 3ft curves, here's my Heljan 31 & 37 together on it.

There's no way they can couple up, and the overhang would cause buffer locking as they go into the curve.

As for trying to run a big diesel with a short wheelbase wagon, again it just isn't going to happen.

 

A lot of this is also down to the buffers & couplings. My American stuff has no problem on these curves as the stock has buckeye couplers and no buffers. But again, below 3ft radius the corners of boxcars start to contact each other, so even with the ideal coupler there are limits to what curves long stock will take, when coupled up.

Run by themselves, I got my US diesels to get through 2ft radius curves, even my 6-axle SD40. But none of them would pull anything through those curves.

 

[goldfish]

On 16/04/2022 at 08:31, F-UnitMad said:

It still depends on what you want to run on sharp curves.

 

I would suggest that is more a question of what is sensible. Short, fixed wheelbase rolling stock and shunter type locomotives are reasonable choices. All but the smallest diesels, HSTs etc., and full length coaches are none starters. Anything below 3' radius can only be sensibly used on something like a shunting plank, so that automatically limits the choice.

 

To show what is possible on 2'reverse curves through points I have refitted Dapol couplings to a couple of my Dapol 7-plank wagons. These two wagons have well matched buffer springs, which is important.

 

Dapol 3-link coupling with wagons being propelled through points. Both wagons are on the same curve, note that he couplings are in tension despite being propelled.

 

 

The point of possible buffer lock as the first wagon passes onto the reverse curve.

 

 

To illustrate the advantages of having longer couplings I fitted one wagon with Dapol Screw-link Couplings. The longer coupling means that there is no buffer contact when the wagons are pulled through the points, and the couplings are not under tension when being propelled through the points.

 

 

Another view of the position of possible buffer lock as the wagons are propelled through the reverse curve.

 

 

If there is a significant difference in the strength of the buffer springs the buffer heads just slip past one another and you get buffer lock.

 

Edited April 17, 2022 by goldfish

[Night Train]

I really like the Dapol screwlink couplings and fit these as standard on my O gauge rolling stock.