TRACKWORK- Transition to Smaller Rail

1785 Bakerfield 2-23 1956 lr

My initial trackwork was built using Right O’ Way Code 125 rail.  It is intended to represent some upgraded track that connects with a busier part of the railroad.  In my case, the busier part is an off-stage connection that terminates into a fiddle yard.   This will allow me to stage trains and consists arriving on the modeled portion of the line.   It also allows me to get unused cars out of sight.   My concept for the staging yard is changing as a result of Trevor Hodges blog called Moreprth in O-Scale.  More on that topic as I start to build that portion of the layout.


My line transitions to smaller rail just beyond the lift bridge.  I am using Right O’ Way Code 100 rail to represent 75# iron for the most of the trackage.  I will be using some Karlgarin Code 82 rail for some 56# sidings and industrial leads.

Transitions are easier now that American Switch and Signal offer Code 125 to Code 100 compromise joint bars that provide the transition in rail size.   The bars are cast in nickel silver (white bronze) and generally fit the Right O’ Way products.  Some files is warranted to get a good fit.

This compromise joint from 56# to 90# rail.  American Switch and Signal makes compromise joints but not for this rail combination.

This compromise joint from 56# to 90# rail. American Switch and Signal makes compromise joints but not for this rail combination. Photo by RW Leach

The compromise joint bars allow you to make a prototypical transition for heavier to lighter rail.   The American Switch parts should be soldered to both rail ends.  As a preparation for installation of the compromise, the tie height needs to be adjusted for the difference in rail height.   In my case, I had to sand down the tie height by .025″ leading up to the joint bars.



I was disappointed to find that little in terms of track details is available.   I ended up using Grandt Line Code 100 plates.  The are of a smaller size than the Weisman Code 125 plates used earlier.  The base is only .015″ thick.  This helps reduce the look of British chairs and bullhead rail.   Track built with seventy-five pound rail should look delicate compared.


You may find it hard to slip tie plates in between the spiked ties.   I found a simple tool to lift the rail slightly allowing the simple insertion of the plate.   I found the tool in a craft store as part of set for shaping clay and other media.


I strongly recommend that consider buying a copy of Mike Cougill’s excellent series of books on building detail trackwork.  You can purchase the book from Protocraft or directly from OST Publications.

The next chapter will deal with building a turnout using American Switch and Signal cast switch parts.


5 thoughts on “TRACKWORK- Transition to Smaller Rail

  1. Hi Gene,
    Your track is going to look good if you follow Mike Cougill’s book. By the way, my Red Cliffs Miniatures also sells his book. I used R-O-W code 125 tie plates with my R-O-W C100 rail. They look much better than C100 tie plates, primarily because of the size of the spike heads. Since the ME small spikes of today have such a bad head, I now use Walther’s C70 spikes. They are the smallest available that I know of. Have fun.


    • Jim
      That is a good suggestion. I used Mike’s blog on turnout construction as a guide along with a lot of photos showing how my favorite railroad built track. I went with the smaller tie plates because they a prototype in size. The small plates look good with the Kemtron X-195 spikes.


      • Yes, mine did too with the X-195 spikes, but I’ve used all I had long ago. If you have any extra, I would surely like to have more for my last 20′ of code100 track in Colfax.
        I was also impressed with Trevor’s well constructed Morepeth fiddle yard.
        Keep up the good work and see you at OSW hopefully. I will be giving a clinic on magnetic operation of the Clouser couplers.


  2. Gene,
    Great post as always. I am currently awaiting the AS&S compromise joint bars as I want to include some code 100 trackage even though it is not prototype–the local logging lines used 85# rail in the 40’s as did the CP line. Incidentally, I have measured its height at exactly 6 inches. or code 125.

    May I ask what was your transition length for sanding the ties under the code 125? I am going to take the opposite tack by shimming the code 100 ties with strathmore board.

    Thanks for your input,

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