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Stretching Peco curves

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Stretching Peco curves
Posted by Clark G on Wednesday, September 2, 2020 9:05 PM
I created a 5x9 mobile layout (separates into 3 parts) I hoped to be big enough to run some of my brass locomotives.  The outside loop is 27” radius so no problems.  The inside loop is 25” and works except for the Peco ST245 & ST244 curved turnouts – just on the larger radius (I know they won’t make the inside 18” deverging  curve).  They work for most locomotives including 2 articulates, but with a 4-6-2 and a 4-8-2 acquired recently I have difficultly.  I then pulled a Spectrum plastic 4-8-2 and it won’t make it. 
They are OK going through the points and frog, but then bind on the curve past the frog.  In researching this, there was a post on Nov 15, 2018 topic: “Shinohara Curved Turnout 24/22, Code 100” which indicated you may be able to cut the ties between the diverging track and straighten them into a wider radius.  Specifically, it was posted by “Railandsail” on November 19, 2018 12:44 PM.  Stretching the curve just slightly on that short about 3” section should solve my problem.
My question is: Is this in fact true, and has anyone actually tried it? 
Many thanks, 
Clark Gregory
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Posted by cuyama on Thursday, September 3, 2020 10:04 AM

Welcome to the forum. Your first few posts are moderated and will take a while to appear, particularly over a weekend. But stick with us and that passes quickly.

The SetTrack double-curved turnouts are very tight. Even the outer path is not much broader than 18” radius, if at all. I think it might be what PECO calls R2, which is 17¼”. Even if were R3, that’s only 19 7/8”. The path is also fairly short. I don’t know if one could cut the web of the ties (sleepers) and adjust it enough. Even if you managed to spread it a bit, this will still be a much tighter spot than your 25” minimum radius.

Although it may not be possible given that it’s the inner line, the best approach would probably be to look at replacing those SetTrack turnouts with the PECO Code 100 Streamline parts (such as SLE87). Though still relatively compact, those have much broader radii.

2” track-center-to-track-center spacing may also lead to sideswiping with some combinations of equipment running simultaneously on the inner and outer ovals (if they are concentric). NMRA standards suggest wider spacing depending on the equipment type.

Good luck with your layout.

Byron

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Posted by Clark G on Thursday, September 3, 2020 11:15 AM
Many thanks for the quick reply and the welcome.  I am a longtime reader of MR and have been here a number of times for good info.  This just the first time I tried to post.  I have no problem with monitoring the first few posts, I am in several Groups.io groups and they all do that. 
It is the outer radius I want to stretch, and it won’t need to be the full 25” radius.  I know there is no way to get my large locomotives around the sharper inside radius, they will be “restricted” from those spurs.  The layout is intended for train shows where the large locomotives will just go roundy-roundy while smaller locomotives work the spurs.  The locomotives sometimes just slow up, sometimes bind and stop and occasionally derail.  So, I think just stretching the radius by an inch or two would make it.  That is why I was intrigued by the above noted post. 
I have been using smaller plastic passenger trains on the inside loop, but it would be nice to have my nicely detailed passenger with the pacific (4-6-2) pulling it there. 
There is no way to put a larger turnout in the space I have and the tables need to fit in my vehicle to get it to shows.  I have thought about just cutting the turnout off just past the frog and putting a piece of flex track there, but if the outer radius will stretch just a little, it will be much easier. 
Many thanks,
Clark Gregory
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Posted by dknelson on Thursday, September 3, 2020 11:53 AM

I recollect an article by Pelle Soeberg in MR about doing this with Peco turnouts: cutting the web beneath the rail so that in essence the track becomes flex track, within reason of course.  I do not recall if he created a bit of curve on a regular turnout, or enlarged the radius of a curved turnout.

I have not tried it myself and I admit that I would have been more willing to give it a try back when Peco turnouts were under $10.

Dave Nelson

 

 

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Posted by Doughless on Thursday, September 3, 2020 12:43 PM

There are forum members who have successfully cut tie webbing to alter the shape of the track by a few degrees, but it may not solve your problem as has been mentioned.

 

- Douglas

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Posted by SeeYou190 on Thursday, September 3, 2020 12:58 PM

Welcome to the Model Railroader forums.

I do not have any experience with Peco HO scale turnouts to speak of, but I do own two brass 4-8-2 and a spectrum 4-8-2. These locomotives need 24 inch radius curves to run reliably.

Just by the description, I think you would be trying to stretch these Peco turnouts too far.

I have had no problems (knock on wood) running these through Shinohara #7 curved turnouts, even thought the inner curve is actually tighter than 24 inches..

-Kevin

Living the dream.

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Posted by selector on Thursday, September 3, 2020 2:26 PM

I learned in short order that I was going to have to mangle all my curved W/S turnouts on my second build in 2006.  The outer radius was pretty solid, but the inner radius was about 3" less than advertized.  So, I inverted mine, all six of them, and cut all of the stringers between the ties on both routes BEYOND the frog...not on the points end.  That got me to where I needed to be, but even that surgery put the routes at the extent of all reasonable limits.  Another 1/2" would probably have started popping the rails out of the spikehead details.

If you do this to whichever turnouts you decide to use, it won't be sufficient to just cut those stringers.  The ones under the outer rail will actually have to be excised to make room for the closure that will take place when you bend the route.

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Posted by Overmod on Thursday, September 3, 2020 2:37 PM

I note the OP said he was only hanging up in the diverging track, so in my opinion the approach should be sound.I As pointed out this is the main, not the diverging curve.  I was not thinking of the switch configuration correctly.  Text below edited slightly to conform.

I think that to maintain gauge without careful use of some kind of Ribbonrail analogue tool, he would want to actually approximate flextrack structure, which is to remove much of the alternating stringers under the rail and perhaps notch or relieve slightly the ones remaining.  Here, on reflection, since he is only opening the curve, he would only remove the stringers on one side, and notch the ones on the other -- the question then becoming which side to remove - if he cut the inside stringers, the outward curving should not require any stock removal...

The gain might not be meaningful for this slight a stretch, but even a slight croggle at a piece of equipment's extreme radius might induce derailment...

Perhaps we need an Ed picture of front and back with the circles and arrows on them showing where he should cut and where he should cut away...

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Posted by cuyama on Thursday, September 3, 2020 5:02 PM

--
Any reason you're using OO track instead of the North American pattern Streamline Peco product? The OO is intended for UK railways.  SL 87 and SL 86.

Both SetTrack and Streamline C100 have basically the same appearance. The Code 83 has the "North American" appearance. 

Likely the original poster is using Code 100 SetTrack because the components are much more compact than Code 83. (As are the Code 100 Streamline, as well)

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Posted by cuyama on Thursday, September 3, 2020 5:05 PM

Overmod
I note the OP said he was only hanging up in the diverging track, so in my opinion the approach should be sound.

He actually said the hang-up is on the outer curve:

Clark G
The inside loop is 25” and works except for the Peco ST245 & ST244 curved turnouts – just on the larger radius (I know they won’t make the inside 18” deverging  curve)

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Posted by Clark G on Thursday, September 3, 2020 8:43 PM

Many thanks for your thoughts, I did look for Pelle Soeberg's articals, there were two on switces, but neither covered flexing a turnout. 

I tried to post a picture marked up to show what I want to do, but it won't let me include a picture and I do not have any cloud storage or good place to save the picture.
Just picture cutting the ties between the main track and the diverging track, farthest from the points, starting just past the frog between the frog rails then bending the main track away from the diverging track probably less than 1/8 of an inch (making it straighter).
Thanks, Clark
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Posted by hon30critter on Thursday, September 3, 2020 9:12 PM

Lastspikemike
SL 87 and SL 86. Outside curve radius is approximately 1 meter which is 40 inches.

According to Peco's website, the outside radius on an SL-86 or SL-87 curved turnout is 1524 mm, or 60". The inside is 30" as stated.

https://peco-uk.com/products/curved-turnout-large-radius-right-hand3

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by rrebell on Thursday, September 3, 2020 10:05 PM

Yes you can modify turnouts but it must be well planned, lost a turnout that I did not plan well enough. I have seen people take a comecial turnout and strip all the ties and hand lay it back with modifications even.

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Posted by selector on Thursday, September 3, 2020 11:27 PM

You have a gauge problem or flashing/high frog if it's the outer route that causes problems.  Does the flange gauge on an NMRA track gauge pass over and through the points, and beyond, past the guards and over the frog without major snagging or dragging?  If you do get some draggning or snagging, that may be where the trouble lies.  Guards not spaced properly, or too wide, maybe even too high, and the frogs can sometimes be complete messes on some turnouts.  Points rails will work fine on one route, but bind up against the flanges on rolling stock the other way.

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Posted by railandsail on Friday, September 4, 2020 7:36 AM

Hi Clark, railandsail here. I am a little confused about your posting.

 

Clark G
I created a 5x9 mobile layout (separates into 3 parts) I hoped to be big enough to run some of my brass locomotives.  The outside loop is 27” radius so no problems.

I believe this 27"r has nothing to do with your question about the curved turnouts??
 
 
 
Clark G
The inside loop is 25” and works except for the Peco ST245 & ST244 curved turnouts – just on the larger radius (I know they won’t make the inside 18” deverging  curve).

If I read it correctly you are trying to insert the curved turnouts into your 25" r loop such that the broader radius of the curved turnout forms a portion of that 25" loop ??

You do realize that the outer radius of those Peco curved turnouts is 22". I documented that here with photos,..
 
 
They work for most locomotives including 2 articulates, but with a 4-6-2 and a 4-8-2 acquired recently I have difficultly.  I then pulled a Spectrum plastic 4-8-2 and it won’t make it. 
They are OK going through the points and frog, but then bind on the curve past the frog.
Basically you are asking these locos to go thru a section of 22" radius,..the outer radius of that Peco turnout.
I'm surprised your 4-6-2 loco didn't make it (what brand is it?).
Your 4-8-2's might have some problems with 22" radius, but considering they make it thru the turnout itself, then have problems with the follow-on track is somewhat surprising. I think I would try adding 23-24" flex track after the curved turnout and see if things got better?
 
In researching this, there was a post on Nov 15, 2018 topic: “Shinohara Curved Turnout 24/22, Code 100” which indicated you may be able to cut the ties between the diverging track and straighten them into a wider radius.  Specifically, it was posted by “Railandsail” on November 19, 2018 12:44 PM.  Stretching the curve just slightly on that short about 3” section should solve my problem.

I recall posting such a link to a video about that, but I can't find that specific one I quoted. The closest thing I could find was this one,..

 

 

 

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Posted by Overmod on Friday, September 4, 2020 11:59 AM

Lastspikemike
I have both Atlas and Peco in my mainline so I'll  have a look later and check that the path of the track through the points is exactiy the same radius as the rest of the turnout or is it straighter?

While you are doing that, see if you can gauge whether the transition from 'straight' to 'curve' is sharper at one end of the points section than the other...

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Posted by Clark G on Friday, September 4, 2020 12:18 PM
Railandsail:
I very much appreciate your reply.  The comment that got me exited was:
2) The Peco ties between the diverging tracks could be cut and spread slightly such that they became an honest 22/18 or perhaps a 23/19.? 
You are correct that I inserted the 22”r outside radius into my 25” loop.  In order to have a mobile layout to take to shows, there is absolutely no way to get the 60”r turnouts into the layout.   I was hoping the 22”r would work and they did for other locomotives including a Tetsudo SP Cab forward (4-8-8-2) and an Akane 2-6-6-2.  (OK: UP 3985 takes sharper curves than 844.)  But a recently acquired 4-8-2 and a Westside 4-6-2, that at the time needed work but is now in service (both brass) almost make the curve but not quite.  They sometimes make it through and sometimes not.  I then dug out the Spectrum and was surprised that it didn’t quite make it either.  So, researching I found your above statement and thought, maybe, that is my solution.  I don’t think I need to stretch it much.
Lastspikemike:
My experience concours what you see, in that once I get to the frog, I do not seem have a problem going through the frog and points.
Note, I also have a bunch of European trains (OO scale), so code 83 is not an option.  In fact, I usually use a German ICE on this loop at shows - way out of place since the layout represents an older time and the rest of the trains are steam, but, hey, the kids get excited.
Again, many thanks for looking at this, your help is appreciated.
Clark
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Posted by Overmod on Friday, September 4, 2020 3:34 PM

Lastspikemike
Well, I eyeballed it as best as I could and nope, the Peco curved turnout doesn't work by offsetting any of the curve. Each curve appears to be a constant radius throughout. 

Thanks.  

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Posted by Clark G on Monday, September 7, 2020 11:49 AM
I replied to Railandsail Friday morning, but the reply hasn’t been posted yet, so I assume it will be posted later this week.
In the meantime, I took a 22” metal curve template and placed over the outer turnout radius and it is well under 22”.  When I lined the template on the stock rails at the rail joints near the points and at the frog, the rail at the far end was off by roughly 1/8th of an inch.  22” is the smallest radius template I had so I placed an 18” piece of snap track on it, and it seems to be closer to that.  These are very crude measurements as they are made laying on top of the railhead.  In his post Railandsail did refer to “become an honest 22/18”.  I have seen these referred to 19 7/8 so that is apparently the outside radius, not 22”.  That was my mistake.
There is no way to get a 60” radius curve on my 5x9 mobile layout (I take to train shows), so if I can’t find a way to expand the radius, I’ll either need to restrict these two locomotives or look for another solution which will require significant re-work.
Thanks, 
Clark

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