Shimming Peco Turnouts

[rickb773]

My last layout was very touchy with crossovers. Light cars, especially small hoppers, would pick the points and derail. I assumed it was due to lack of care on my part during trackwork. One of my fellow club members explained to me that this was a known issue with Peco turnouts. He explained that they were made for both 1:160 and 1:150 scale trains and were a little “sloppy” in the gauging to cover both scales. I was told they needed to be shimmed to improve their performance.

I am sure that this topic has been covered here somewhere but I couldn’t find anything very helpful, so I am going to document my work to help anyone struggling with the same issues.

I found this picture somewhere. (If anyone knows where let me know and I’ll credit the source). It shows what must be done.



Here are the products I used to make corrections.

For shims I ordered Everygreen black .010” Polystyrene sheets (White will show even if painted, because sooner or later you will clean the turnouts and the white will again show through.)



To hold the gap open and press the shim to the guardrail I used some brass shim strips (Amylove .016”).



The club told me they had used “Tenax 7R Plastic Welder” as glue but evidently it was no longer made. An eBay seller claimed Styrene Tack-It II used the same formula so I ordered some on eBay. It was useless. I then tried some AC glues I had available but they also proved ineffective. Then I tried “Fallers Super Expert” glue and it was very effective. If you are going to use this Faller’s product you will need a very small wire to keep cleaning the application spout wire as it quickly solidifies even when you quickly return the bottle cap. I think it is a music wire, but I do not remember the size.





Start by taking an X-Acto knife and cutting the polystyrene sheets into ~1.5mm wide strips. Then cut 20mm lengths for Peco medium turnouts and 23mm for Peco large turnouts.



I put shims in both guardrails shown on the diagram. I do not believe you need to do the one guarding the straight turnout pathway. I’ve only had trouble using the curve routes. You can decide if you want to live dangerously and only do one. 😊

Add glue to sparingly to the outside of each guard rail.



Insert a shim.



Use the brass shim to hold the plastic shim in place with one hand and use an X-Acto knife to bend an end to conform the shim to the leading edge’s angle. 25-30 seconds and it should be in place. You should now have time to use the X-Acto knife to bend the other end of the shim to the other lead angle. Hold another 20-30 seconds. Then trim the excess length of the shims.

I understand my model railroad club had a jig to make this easier, but they could not find it.



Put aside to fully dry and start the next turnout.

The next day I would come back and trim the shims with a very very sharp X-Acto knife to the height of the existing guard rail.



Then I would take a piece of sandpaper and smooth the shim tops.
Check that the pathway is clear of any obstructions.

I hope this helps you get better performance (i.e. less derailments) from your Peco Turnouts.

Keep ‘em rollin’,
Rick

[Tad_T]

Nicely done, sir.

[John]

Good tutorial. Most of the mags would have these types of articles back in the day.  I don’t have many peco switches left since I switched to the atlas code 55 (with their own problems) a long time ago

[Maletrain]

Thanks for the discovery of a glue that seems to work on the Peco turnout plastic parts.  I will be ordering some.

I am wondering how well the plastic shims will hold up under use.  If they start letting go, please advise us via this thread.

That said, at our club, we had a problem with a Peco turnout that was installed some time ago (maybe as much as 40 years ago), where the plastic guard rail had actually worn down on its approach edge, so the wheel flanges started picking the frog point and causing derails.  My solution for that was much more difficult, but probably longer lasting - I ground out the guard rail and replaced it with a metal one made from code 80 rail.  That was epoxied in place with a 0.030" spacer between it and the running rail, which was then removed.  That seems to be holding up and working well.

Although I did grease the shim, it was styrene plastic and I had to get it out as soon as the epoxy started to set, so that it would not become a permanent part of the turnout.  I am going to buy some teflon to make the spacer if I have to do that again.

[dem34]

Thanks for the discovery of a glue that seems to work on the Peco turnout plastic parts.  I will be ordering some.

I am wondering how well the plastic shims will hold up under use.  If they start letting go, please advise us via this thread.

That said, at  our club, we had a problem with an Peco turnout that was installed some time ago (maybe as much as 40 years ago), where the plastic guard rail had actually worn down on its approach edge, so the wheel flanges started picking the frog point and causing derails.  My solution for that was much more difficult, but probably longer lasting - I ground out the guard rail and replaced it with a metal one made from code 80 rail.  That was epoxied in place with a 0.030" spacer between it and the running rail, which was then removed.  That seems to be holding up and working well.

Although I did grease the shim, it was styrene plastic and I had to get it out as soon as the epoxy started to set, so that it would not become a permanent part of the turnout.  I am going to buy some teflon to make the spacer if I have to do that again.

The glue shouldn't break, since he used plastic cement it fuses the two pieces together by melting the parts then solidifying once the chemicals evaporate.

But didn't realize this was one of the issues, when I hear shims on Pecos I usually think of putting the .30 shim in the frog to stop wheel drop. Which was my main bugging point for derailments since stuff would bounce, misalign, then catch.

[nkalanaga]

The frog issues are also the result of too-wide flangeways.  Modern North American N wheels are too narrow for the wide NEM flangeways.  The frogs/wing rails could be shimmed the same as the guardrails.

I don't remember what I used to glue my shims, either Testor's liquid cement or ACC, but they're still holding after 25 years.

[peteski]

Excellent write-up and a suggestion to use black styrene which will stay pretty much invisible even when it is abraded by wheels.
Friend of mine did this on his layout years ago (using white styrene).

Since Peco turnouts are designed to be compatible with European deep flange wheels dem34's suggestion to make the frog's flangeways shallower is also a good one, especially for turnouts and crossovers with long shallow angle frogs.

I'm also curious about the ingredients in the cements Rick used.

[NtheBasement]

I don't have crossovers but I do have turnouts like the diagram.  I don't think I've ever noticed a derail at the frog itself, just picking the points on the point rails which are nowhere near the points.  I have bent (carefully) a point rail tip or two slightly so it jams against the side rail better on a few of my turnouts to make sure the gap gets closed.

I have many Peco c55 turnouts on my layout and my cars have MTL trucks.  I do see my hoppers wiggle as the wheels drop into the gap in the frogs.  Thanks @dem34 for the fix, but did it cause problems for any of your locos?

[Point353]

I found this picture somewhere. (If anyone knows where let me know and I’ll credit the source). It shows what must be done.

https://forum.trains.com/t/wheels-jumping-on-frogs-of-peco-streamline-n-scale-turnouts/169147

[jdcolombo]

Excellent write-up. 

Only one suggestion I'd make: to get the edges of the shim attached at the appropriate angle, I used a round wooden tooth pick.  Break it into two, and then insert the pointed end of one half between the rail and the plastic shim.  I found that the angle of the point on the toothpick was basically perfect for holding the end of the shim against the guardrail while the glue set.

And I used Testors Liquid Plastic cement with success in gluing the shim to the guardrail.  I used Peco turnouts with shims for about 8 years before building my current layout with Atlas Code 55, and I never had a shim come off when glued this way (with liquid plastic cement); there are Peco turnouts on our club's Ntrak yard modules that have been there for 30 years with shims, still going strong.

If you do this, however, you will need to make sure that your engine and rolling stock wheels are absolutely in gauge using the NMRA gauge.

John C.

[rickb773]

https://forum.trains.com/t/wheels-jumping-on-frogs-of-peco-streamline-n-scale-turnouts/169147

@Point353 And that author says he grabbed it from some forgotten source.

[mmagliaro]

The plastic in those Peco turnouts is a slippery "engineering" plastic  (might be Delrin, but I don't really know).
I never had good luck getting any liquid plastic cement (Tenax, Testors, Bondene, you name it)  to really bond a
stryene strip in those flangeways.
It melts the styrene part, and it does seem to stick in place, for a while.  But it's not really bonded.
The same was true for 2-part epoxies.  They sort-of stick, but not really.  I found that the shim
could always be easily picked out with the tip of an Xacto blade.  They mostly stay put because the wheels
always come through the flangeway so that the flange presses on the shim.  There is almost never any force
trying to pick or pull the shim away.
Anyhow, I finally settled on Walthers Goo.  Yes, I know it is flexible and rubbery (and messy, and a pain to work with),
but when that stuff finally does set up after a couple of days, it really grips.  It's one of the very few adhesives that
can actually stick to Delrin.   This was a walk down memory lane.  I haven't thought about shimming Peco turnouts
since I last used them about 20 years ago.

[nkalanaga]

One problem I had with Peco points is the end of the point itself.  The only ones I have are in my closet staging yard, where I have four of them.  The shims work fine, but two of the four had derailment problems on facing-point, curved-route moves.  Since all four should be identical, why just those two?

Turns out that, 30 years ago, when I bought these, there were two styles of points in use.  One had plain, vertical, "blunt" ends.  The other had the top corner cut at a 45 degree angle.  The blunt ones worked fine.  The angled ones would NOT work with small flanges.  The flanges simply rode up the angle and over the point.  The solution was to buy two new turnouts, making sure I got the ones with blunt points.

[dem34]

I don't have crossovers but I do have turnouts like the diagram.  I don't think I've ever noticed a derail at the frog itself, just picking the points on the point rails which are nowhere near the points.  I have bent (carefully) a point rail tip or two slightly so it jams against the side rail better on a few of my turnouts to make sure the gap gets closed.

I have many Peco c55 turnouts on my layout and my cars have MTL trucks.  I do see my hoppers wiggle as the wheels drop into the gap in the frogs.  Thanks @dem34 for the fix, but did it cause problems for any of your locos?

Only engines I had issues with was a Graham Farish Black 5, and a 90s vintage Kato SD40. Presumably if something was made in the last 30yrs it should be fine. Even from places like Japan as I first heard of the fix from a Japanese modeller. Its mostly just European models that seem to still be made with the expectation of giant flanges.

[randgust]

I've never had enough issues with Peco turnouts to have to shim, but I don't use low-profile wheels, either.

What I have had issues with is the electrical pickup to the points.   As a result, when I get a Peco switch in, I solder a tiny feeder of braided wire (usually with the insulation stripped off) and join the points to the stock rail on both sides before the frog.  Then the switch gets painted.   The leftover wire scraps from decoders works rather well.

Yes, it's a miserable thing to do, but with short wheelbase steam it's pretty necessary.

The other thing I've gotten used to is that the built-in spring isn't quite enough to give reliable electrical contact.   I tend to pull them out and replace it with a caboose hobbies ground throw to increase the closing force on both sides.  On electrofrogs I tend to use Tortoise machines to power the frog side as well using the slide contacts.

But with all that, yeah, those are incredibly durable and bulletproof turnouts.