S Scale Variants - Flyer vs Hi-Rail vs Scale

There are three schools of though when it comes to modeling in S Scale.


American Flyer style coupler on an S-Helper covered hopper.

The original American Flyer wheel has a wider tread and larger flanges. The wider tread leaves less space between the backs of the wheels requiring larger gaps at the points and frogs of a turnout as well as wider spacing in crossings. Most rolling stock in S Scale is equipped with this style wheel while some items include both. This means most S Scale equipment can run on American Flyer track without modification.

Due to the larger flanges, sometimes called pizza cutters, thicker rail is needed to prevent the wheels from contacting the ties as they roll along the track. While Flyer wheels can work on Code 100 (0.100" height), most track designed for Flyer used a larger code. Some hand laid products were available with Code 125 (0.125") rail but most were produced with Code 138 (.138") or larger rail. We are offering our Hi-Rail turnouts in the following codes:

  • Code 125. This matches some older switch kit products designed to use a smaller rail that was readily available.
  • Code 138. This rail was used by S-Helper Service (and then MTH) and Fox Valley Models. It is very close to what Lionel used to produce their FasTrack product. Our rail has a slightly different contour but works well with all of these products.
  • Code 148: While only slightly larger than Code 138, this rail is used on American Models track.

The disadvantage to using this thicker rail is the non-prototypical look of the rail compared to the size of the car.

Flyer equipped rolling stock also has a larger coupler as seen in the photo. As with the wheel sets, most S Scale rolling stock comes with this style of coupler. 


Kadee 802 coupler

Hi-rail modelers generally keep the larger wheels as they can be difficult to change on older equipment made by Gilbert and American Flyer. To get a more prototypical look they change the couplers to something closer to scale, such as the Kadee 802 designed for S Scale. This coupler comes with a draft gear box that many S Scale products, including S-Helper and American Models, were designed to accommodate.

By changing to a more scale coupler, the rolling stock will couple closer together for a more realistic appearance. However, since the larger wheels are used, these cars generally need the larger code rail and wider points and flanges as the American Flyer equipment.


In an attempt to make their trains look as close to the real thing as possible, many modelers choose to use wheels and couplers that more closely match the prototype. Scale wheels have a narrower tread and a much smaller flange and have a more prototypical contour. Coupled with scale couplers these cars look much more like the real thing rolling down your track.

Since scale wheels have a narrow flange the gaps between points and frogs on a turnout can be closer together. This allows for a more prototypical look for the track. Additionally, with the smaller flanges, smaller code rail can be used for an even finer look. We offer our scale track and switches in the Code 70, 83 and 100. Note: Scale wheels that do not follow the RP-25 NMRA standard may make contact with the tie detail on our Code 70 flex track. Scale wheels from S-Helper, MTH and Scale Trains all have an RP-25 contour and run well on Code 70 rail.