Aristo-Craft Wide Radius Turnout Improvements

Aristo Wide Radius Turnout improvements Vignette
(Improving upon Aristo-Craft's Wide Radius Turnouts so as to avoid derailments of locos and rolling stock.)

Ted Doskaris
May 4, 2007
Revision GE-C

November 26, 2013
Revision GE-D1  Added Guard Rail Height info., Appendix A & Appendix B about Replacement Frog, & Guard rail shim method

February 13, 2014

Revision GE-E Appendix C Method for Point Rail Fix on a S.S. Turnout; Added Electrical Jumpers; Turnout Tested In an 8 ft. dia. Track Circle

(Note: There is a complementary page on Aristo Wide Radius switches that you should read at: )

To preface, Aristo-Craft appears to have several versions of their Wide Radius Turnout. All versions have a plastic frog:

1) The first generation version is identifiable by having brass guard rails opposite the frog – a good thing – though spaced too far from their main rails to be best effective.

The first generation turnout’s Frog also includes metal wing rails:

2) The second generation version is identifiable by having plastic guard rails with abrupt transition ramps – again being spaced too far from the main rails.

The second generation turnout’s Frog includes plastic wing rails:

3)    The third generation version is identifiable by having metal straps rather than jumper wires at the base of the point rail pivots for power pickup. This version also includes plastic guard rails. The third generation version was offered in both brass and stainless steel as shown in the below example:

The third generation turnout’s Frog also includes plastic wing rails:

Below is an overall bottom view of the 3rd generation version:

By now there maybe a newer generation Wide Radius Turnout; however, this article is limited to the aforementioned versions.

The plastic frog:

Before I addressed the guard rails I decided to take a look at the plastic frog on my example turnout which is a brass second generation version.

I noticed all of my Aristo Wide Radius turnouts - including all versions thereof - have the plastic frog protruding above the adjacent rail heads with some worse than others.
This causes rolling stock (and especially the locos) to bounce over it when traversing the turnout!
Under some situations this results in derailments or losing consistent propulsion with track power.

I employed a fix to my example turnout that many other folks had done before me by placing a shim under  3 of the 4 rails on either side of the plastic frog to improve their vertical alignment. The shims I used were flat washers meant for 2 mm screws that measured about  .012 inch thick.
However, whilst this method works well for most locos and cars, I later discovered that it does not best accommodate the operation of Aristo's 2-8-8-2 Mallet loco.
This is because there is a slope caused to either the frog and / or adjacent rails with the installed shims. When backing up the Mallet toward and past the frog's point the Mallet’s rear most driver wheels will rise high enough to expose their flanges on the downward sloping rails! Apparently some of the Mallet driver axles do not offer much in the way of vertical movement for track irregularities.

Given this experience, my future frog modifications to existing turnouts will use a different method.
In this regard, perhaps Aristo-Craft may consider addressing the issue of the frog being too high with a factory process change such as milling the top surface of the plastic frog to be exactly even with its butted, adjacent rail heads. If fact, Aristo did produce a Replacement Frog.  See Appendix A for information about this frog.
Perhaps the plastic frog’s mold design dimensions need to be examined with respect to its dimensions in consideration of the process after the frog part is made. This may be causing undesirable dimensional differences that may be responsible for the frog being too tall.
Finally, the frog's flange way channel must be deepened, too, as will be described and shown later.

The screws holding the rails to the under side of the ties were temporarily removed to facilitate the installation of the shims as shown in the example picture:

Now for the Guard Rails:

The original plastic guard rail to main rail clearances measured anywhere from .125 to .135 inch.
This is too much and in conjunction with their abruptly angled transition ramps can cause derailments when a loco with body mount type coupler is pulling a heavy train through the diverging path with the first attached car having a truck mount type coupler.
In this regard, the below picture illustrates the lateral coupler force exerted on the truck mount wheel set via body mount loco coupler that forces the leading car wheels toward the frog whilst striking the guard rail's abrupt transition ramp. Thus, the car is apt to derail because one wheel flange on the first axle wants to strike the frog’s divider point whilst the other wheel flange on the opposite side wants to hit the guard rail’s abrupt transition ramp:


There are couple of methods to remedy the guard rail issue. One is to fasten a shim to the surface of the existing plastic guard rail.  See Appendix B for this method.

Another method is to fabricate replacement metal guard rails.

I fabricated two new guard rails, each about 4  3/8 inch long from a salvaged brass track.
Using a bench grinder I ground off the base flange to allow each guard rail to fit against the main rail with a clearance of .106 inch - which is the NMRA specification for #1 or “G” turnouts.  
(I also ground relief notches to clear one tie "fish plate" and to facilitate the bending of the transition ramps.)

Top view showing 2 fabricated brass guard rails with gradual transition ramps:

Then I removed the diverging main rail that is best done by pulling it out from the points end of the turnout. (Note there are typically three 2 mm screws you must first remove that are located on the underside of the ties.)
Removing the main rail exposes the plastic guard rail that is to be removed as seen in the picture:

I cut off the plastic guard rail using a Dremel tool with large cutting wheel attachment as shown:
(Other cutting methods will probably work, too.)

Similarly, I cut off the plastic guard rail on the other side of the turnout after removing its main rail.
The picture below shows how you can use the Dremel tool for grinding away at the surface to remove a little more material:

You can do the final (flush with the ties) finish by using a file:

The below pictures show the turnout with the plastic guard rail removed flush with the ties whilst still retaining its webbing attachments:

Then I drilled and tapped the under side of the fabricated brass guard rails for 2 mm fastening screws using Aristo's 2 mm drill and tap set as shown. (I first determined where the holes should be by placing and aligning the guard rails on the ties and marking them.)

Only the two outside holes are needed for each guard rail; the third one as seen was already in the rails.

Once the original plastic guard rails are done away with new holes can be drilled in the ties to mount the fabricated brass guard rails. I used the pin vise with a drill size of .071 inch (#50) then opening it up - if needed - to .108 inch (#36) max. for locating the fabricated guard rail to be .106 inch distant from the main rail:

These pictures show the completed installation of the two new brass guard rails:

The following turnout bottom view picture serves to contrast the original plastic guard rail abrupt angular ramps to the fabricated brass guard rails that have more transitional ramps.
(The more gradual transition ramp prevents the loco and car wheel flanges from hitting the otherwise abrupt ramp angles that can cause derailments.)

Top view picture:

Now the Wide Radius Turnout has its newly installed guard rails with a proper NMRA specified location of .106 inch from the adjacent main rails:


Important consideration about guard rail height:

Never allow the guard rail height to be lower than its adjacent stock rail. It's best that the guard rail be slightly higher. This is particularly critical for the relatively tight curve for the diverging path of the not that wide "Wide Radius" turnout, or you will invite a loco going over it to derail as its leading wheel will tend to climb over the guard at the wing ramp.

In fact, I had to elevate the guard rail slightly above the stock rail to prevent such an occurrence that I had experienced in the example Aristo WR turnout shown below.

Even with the long guard rail in this example, until I elevated it, a loco wheel would climb up on it.

Elevating the guard rail can be done by adding a thin washer under each of the two screws that fasten it to the plastic bedding.


Elevating the guard rail stopped the wheel climbing tendency for good.


Back to the plastic Frog:

Aristo's Replacement Frog is described in Appendix A.
The following discusses a possible fix for the original Frog:

Below are a couple of example pictures of the plastic frog. The frog problems are the same for all 3 generations of Aristo’s Wide Radius Turnouts.

Aristo-Craft Second Generation Wide Radius Turnout Side View showing plastic frog top surface projecting slightly above its butted, adjacent rails.

The End View showing plastic frog top surface projecting slightly above its butted, adjacent rails.

The channel for the wheel flanges must be made deeper to prevent the wheel flanges from riding up over the top of the frog. From my measurements, the Aristo Diesel loco wheel has a bigger flange radius by approx. .015 inch when compared to the Aristo ART-29111 metal car wheels. In this regard, it seems the frog channel is optimized for the car wheels - not the loco wheels!
I used a flat file on its narrow side to remove enough material to allow the Diesel wheel to pass over the frog without rising up. (It is easier to do this with the end rails removed before you shim them as a fix for the frog being too high.):

Wheels shown now roll over the plastic frog without rising above it (The bigger Diesel wheel with its larger flange is seen on the right):

Gravity test of the point rails:

You can do what I call a gravity test for the point operation as shown in the below pictures.
(I find doing this test helps assure Aristo’s powered turnout motor will be able to operate the points once everything is installed in the layout. If the point rails do not fall to the main rails, you must adjust the various screws to allow for free operation.)

The point rails should freely drop toward the straight rail:

Then flipping the turnout around, the point rails should freely drop to the curve rail:
(Repeat these two gravity tests to check for operational consistency.)

When done adjusting the screws after removing any possible obstructions, I apply some Loctite 222 to the exposed screw threads at the point rail tips. (I do this because those screws will eventually work loose and fall out due to vibration with repeated train operation.) You can also Loctite the pivot screws if you first remove them and put a very small drop in the screw hole whilst repeating the gravity test as needed as the screws are threaded in.




Appendix A - Aristo's Replacement Frog

The purpose of the Frog is to provide a traversable crossing path for train wheels to go through both straight and diverging paths of a turnout without disruption. It appears to be called a Frog due to the resemblance of a frog's stretched out fore and aft legs.

Shown below is the Replacement Frog for the Aristo-Craft Wide Radius Turnout.

Aristo eventually addressed the Wide Radius turnout frog problem with a retrofitable replacement frog that could be ordered from Aristo to repair the turnout without having to modify the original frog.

The top view of the new Replacement Frog is included in the picture shown above. The first impression is that the Replacement Frog does not look different from the original.

The Original Frog is shown below.

The following pictures will serve as a comparison of the two Frogs (examples of 1 Original & 1 Replacement):

When the Frogs are measured, the differences can be seen.

Shown below is the thickness of the ORIGINAL FROG.

Shown below is the thickness of REPLACEMENT FROG. The replacement Frog is a desirable 0.011 inch thinner than the original Frog.

Shown below is the measured flangeway depth of the ORIGINAL FROG.

Shown below is the measured flangeway depth of the REPLACEMENT FROG.

The replacement Frog at a 0.128 inch depth is a desirable 0.016 inch greater than the original Frog. This is close to the wheel flange height of 0.132 inch of many "G" scale locos. Hence, such a loco passing over the replacement Frog is much smoother and works very well.

Shown below is the Replacement Frog installed in an Aristo stainless steel Wide Radius Turnout.

The direction of the Frog point is shown in the above picture; the opposite direction is shown in the below picture.

Notice the plastic guard rails are cladded with a metal shim. This is described in Appendix B.


Appendix B - Guard Rail Shimming Method

As an alternative to removing the Aristo WR turnout plastic guard rails and replacing them with metal guard rails, the plastic guard rails can be built up by using a shim. This is a simpler, quicker and more traditional method done by many folks in the past. Though I don't think this method is as good as using replacement metal guard rails, I decided to try the shim method.

Shown below is an Aristo Stainless Steel Wide Radius turnout fitted with metal guard rail shims.



Shim Material

Since the WR turnout's plastic bedding can vary in dimensions depending on the process when molded, the required shim thickness can vary for different production runs. In the example WR turnout to be described, I determined an 0.008 inch thick shim was needed for diverging path of this particular example based on measurements made for the distance between the plastic guard rail to its adjacent stock rail. The measurement for the straight path would call for a thicker shim. For outdoor use, I decided to use stainless steel shims for this stainless steel turnout.

The shim is cut so that it is slightly taller than the main stock rail. Since rail used is code 332 (0.332 inch tall) the shim was cut using a shear to be 0.350 inch. I determined that this slightly taller height prevents train wheels from climbing over the transitioning wing - which can happen under certain circumstances.

The available material I had was in a roll measuring about 4.6 inches across, which after shearing it, I cut off to be 4.1 inches

To prepare the turnout for the shims, the main stock rail is to be removed, doing one shim installation at a time. There are several small 2 mm screws on the underside that hold the rail in place that must be removed, then the stock rail can be pulled from the plastic bedding. Shown below is the straight path. The curve path is similar to do:

With the stock rail removed, it's easy to mark where the bends are to be made in the shim so that it conforms to the wings on the plastic guard rail. With the precut to length shim centered near the guard rail, the bend locations can be marked with a pen. I used a black Sharpie thin tip pen.

Some of the tools I used for making the bends are shown below.

Placing a small vise flat on its side on a smooth surface work bench can be used to make a squared up bend. Slip the shim with the marked line into the vise then bend the shim to match the angle of the plastic guard rail wing.

If the bend angle is off slightly, you can correct it with pliers or put the shim in the vise and squeeze it a bit.

The corners are bent using the small pliers so the shim will have a mechanical fit at the ends of the plastic guard wings. This assures an enduring fit without requiring total reliance on gluing alone - beneficial in an outdoor environment.

Before gluing the shim to the plastic guard rail it is cleaned with alcohol using a Q tip in preparation for using CA type glue.

Before gluing the shim to the plastic guard rail the plastic surface gloss is removed by sanding , then cleaned with alcohol. This provides for a better bonding grip.

A bead of CA type glue is placed over the length of the shim.

The shim is then slipped down over the top of the plastic guard rail with its ends enveloping the "wings".

Small clamps are used until the glue dries (This type CA glue has some working time before it sets.)

The shim is now completely secured.

Notice how the shim extends slightly above the plastic guard as intended.

Shown below is an overhead view of the turnout area of interest with the stock rail re installed.

Shown below is the distance being measured between the guard rail and stock rail at the diverging path. It measures 0.106 inch which is the desired target value.

The Aristo-Craft track gauge (ART-11906) can, also, be used to verify the desired 0.106 inch width distance.



Appendix C Point Rail Fix, Jumpers Added & Test in 8 Foot Dia. Track Circle

Fixing Swinging Point Rail on Stainless Steel WR Turnout:

When some of my locos would attempt to go through the turnout facing the point rail, their wheels tended to ride up over it and then the locos would derail. Examining the point rail showed it was ever so slightly too far from the stock rail. The cause is due to the cross section shape of the stock rail that it is not straight up & down but tapered toward the track ties (sleepers) such that when the point rail is against it there is a gap at the top. The gap is not too noticeable with the naked eye, but very noticeable when using a magnifying glass. The solution is to grind the taper off the side area of the stock rail where the point rail meets it so that it is vertical whilst being careful not to grind into the rail's head. This allowed the point rail to be positioned closer to the stock rail with minimal gap.

The swinging point rail of the diverging path is modified as described in the below picture.


Augmented Electrical Jumpers:

For track power applications when operating several MUed locos in a layout, high currents can result in noteable voltage drops. Thus, it's behooving to augment the small wire gauge jumpers that the turnout comes with. I used short length AWG 14 gauge stranded copper wire with crimp lugs that I, also, soldered. As can be seen in the below pictures, the jumpers are held in place at the Split Jaw rail clamps.


Putting the WR Turnout in an 8 Foot Diameter Track Circle:

The Aristo Wide Radius Turnout appears to have been designed with the intent of placing it with a 10 foot diameter circle of track; however, it can, also, be placed in an 8 foot circle of track with virtually no noticeable mismatch.

Though the diverging path is slightly less sharp than an Aristo 8 foot diameter track section, it is almost the same length (being a little more than 1/4 inch longer).

When placed in an 8 foot diameter track circle, the turnout path curvature is so little different from an 8 foot section of track as to be virtually unnoticeable.


Testing the Modified Aristo WR Turnout in a 8 Foot Dia. Tack Circle:

For convenience sake, testing the debugged, modified WR turnout was done indoors by installing it in place of one track section within an 8 foot diameter track circle as shown in the below pictures

The video below shows a couple of different locos and short length train traversing the modified Aristo WR turnout.

(Be forewarned, I suffer from periodic sinus congestion, so my "throat-clearing", as I was taken to task about as commented on Youtube, may be annoying. If so, mute the audio or don't view it at all.)






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