Modules: Free-mo

The Free-mo modular layout is built on the concept of allowing greater freedom in module construction and design, with an emphasis on following prototype design and practices, while still remaining portable.

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Free-mo S Standards

Free-mo layouts feature just a single mainline, and can be used for point-to-point, point-to-loop, loop-to-loop, or continuous-run oval set-ups.

The Free-mo standard only specifies the end plates of the modules to be two feet wide, so that modules can be rotated end-for-end and still work.

Officially, there are no S-scale standards developed for Free-mo at this time, as many in the S community feel that the NASG's S-MOD standard accomplishes the same thing. Nonetheless, some are developing Free-mo standards for S, Sn3, and Sn2. The real practical difference in the two standards are heights of the top of the rail, and Free-mo only supports DCC. Free-mo encourages more prototypical appearances and discourages continuous-running, but those are not requirements, and the S-MOD standard can be used in the same manner. If you feel strongly about these movements or are interested in building your own modules, consider checking out some of the resources listed further below.


There are currently three known S-scale clubs that have a Free-mo style of layout. These are the "S Scale Workshop", the "Sn2 Crew", and the "Bay Area S Scalers".

S Scale Workshop

This Canadian group used to have an older sectional layout that they took to local shows. As the members started aging, the heavy modules started having a toll on the members' muscles and bones. So, the club decided to abandon the old layout and start over again. In their research for what kind of layout they might want to build, they stumbled upon Free-mo, and decided to pursue that in S-scale. Since there was no S-scale standard for Free-mo-style layouts, they experimented and came up with their interpretation of the (HO-scale) standard to set their own guidelines.

The club's layout has won two "Best in Show" awards at large train shows in Milwaukee, Wisconsin and Springfield, Massachusetts. The club sets up their layout in various configurations, but they are all generally point-to-point. It all depends on who is able to bring their modules to a particular show. This also draws attention to another big benefit of having a Free-mo design within a club, and that is that not all modules are required to have to be there, or even some critical ones. The S Scale Workshop use a conventional turntable to turn engines at one end, or they use a three-track whole-train selector plate (mimicking British display layouts), or they have a large balloon loop at one end. They use code 83 rail on the main line, and code 70 rail on the sidings.

S Scale Workshop web site.

club member Jim Martin gives a guided tour of their layout during a 2013 NASG Convention clinic; copyright © Peter Vanvliet; used by permission

Sn2 Crew

This group is not a formal club, but rather a group of individuals interested in Sn2 modular layout modeling, taking their individual modules to various shows. The group has no web site and communicates via e-mail, since members are scattered around Pennsylvania, Ohio, Maine, and Maryland.

Lee Rainey with his home layout, which incorporates modules he uses with the Sn2 Crew public display layout; copyright © Bill Winans; used by permission
Setup at the 2014 National Train Show; copyright © Lee Rainey; shared on the S-scale mailing list

Sn2 Crew at 2014 Cleveland Show (video)
Sn2 Crew at 2010 St. Louis Show (video)

Bay Area S Scalers

This club draws members from California, and they decided to model prototype railroading in a modular fashion. When they decided to build a Free-mo-style layout, they drew up standards based on what the Canadian S Scale Workshop club had established for their layout. These standards are available as a PDF file for download via their BASS web site. Their first public showing was in May of 2017, which showed a loop-to-loop layout. Photos can be seen on their web site.

Bay Area S Scalers web site


Use of Circuit-breakers

When using circuit-breakers on individual Free-mo modules, the ability to rotate a module 180 degrees may cause the circuit-breaker to not work correctly anymore. Rotating the module may cause the rails' polarity to be different to adjacent modules, as far as the circuit-breaker is concerned. This can be corrected in two ways; change the connectors of the DCC cable around, which is the easiest solution, or change the track cable connectors around, which can be confusing.

Sn2 Track Standards

The Sn2 Free-mo standard states that #8 turnout frogs should be used. However, upon careful reading, the standard indicates that only for when the turnout is used on the mainline and the mainline is the diverging route of the turnout. This is because the Trains & Trooper Forney locomotive requires a #7 turnout. If the mainline is through the straight track of the turnout, then any numbered frog can be used. For curves, the recommended minimum is a 36" radius, for the same reason.

The Sn2 standard says "S3.1 Modules shall use hand-laid track or flex track". "Flex track" is to be interpreted as commercial track, but since there is no Sn2 commercial track system available, this can be interpreted as being HOn3 track by any manufacturer.

The Sn2 standard says "S3.10 Track on the through route shall be code 70". This only applies to the ends of the modules that are to be connected to another modeler's modules; within a module or a "permanently-coupled" set of modules, the rail code can be code 55. The bottom line is that the module builder is responsible for making the transition to code 70 at the ends of the modules, or provide fitter rails that transition to code 70.


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