Monday, September 14, 2020

Modifying guardrails on Peco turnouts

Almost 30 years ago I attended an informal clinic during an Ntrak club meeting on modifying Peco turnouts by adding a .010 shim to the inside of each guard rail to prevent the inside wheel flanges from hitting the frog.   This method became something of a standard for the members in the group and it is something I have always done prior to installing Peco turnouts on my home layouts and Ntrak modules.   I don't add this shim to my code 55 turnouts on my Asia prototype modules as some of the equipment run on that layout has thicker flanges and the shim would make the guard rail too tight. 

This photo illustrates what happens when the space between the outer rail and guard rail is too large.  When allowed to slide inward the inner tab of the gauge can hit the frog.





These are the materials I use for this project.

Super glue, Black sharpie pen, Hobby knife with new blades, .010 styrene strips about .125 in width, several tooth picks or push pins.



The strips are cut to a length just a bit longer than the guard rails and one side is blackened with the sharpie pen.





The side that is not blackened gets a fine bead of the super glue along it's length and is placed into the space between the rail and the guard rail with the glue side facing the guard rail.  Tooth picks or push pins are pushed into place to hold the strip against the guard rail while the super glue sets.



Next the excess strip is carefully cut away with a hobby knife making it flush with the guard rail.  The rails are used as a guide.  Any excess of the strip that extends beyond the guard rail is also removed.  This is where a nice new blade in the hobby knife pays off.



The shim should match the height of the guard rail and the edge is colored with the black sharpie pen.  As seen in this photo the gauge passes through without the inner tab hitting the frog.



  1. After adding the DCC Specialties circuit breakers to my layout a few years ago Brad, I was getting shorts in places that I never had before with locos that ran without a hitch.

    Did a little research came up with this solution as well and went back and installed the shims on my turnouts as well. Worked like a charm.

    One piece of advice that I got a from a member on a forum I belong to was to use some .010 shims made from BLACK styrene. By using black styrene the black marker didn't get removed when you cleaned the track leaving a fine stripe of white showing through.

    Just a suggestion that worked out for the better.

    1. Hi Allen, I remember you mentioning those odd shorts. We actually started doing this before DCC became a thing, it was to prevent derailments.

      That is a good idea to use black styrene. I know Evergreen makes it but I have never seen it carried by my local shop and they have the most impressive selection of Evergreen that I have seen.

    2. Yup I had heard others doing years ago as well to narrow the gap between the rails and guardrails.
      As for the black styrene, I found mine on eBay. Looked just now and found these:

  2. Yep been there done that on a layout back many years ago when a guy we once hung out with went to DCC. Made a huge difference.