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


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.
OR
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:


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:



Back to the plastic 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.


End