The S-MOD System of Module-Railroading
(This introduction contains excerpts from the NASG S-MOD standards and from articles by Don Thompson and Don DeWitt, as published in the “S-Gauge Herald” and the NASG “Disptach”. These standards and articles are copyrighted, and excerpts are used with permission from the authors and NASG.)
The basic idea of modular layout systems is that individual modelers can construct sections of layout which can be brought together and assembled into an operating layout. This is accomplished by adhering to physical standards (height and track alignment at the mating ends) and electrical standards (connectors, control scheme). In addition to being assembled into a large layout for local and national shows and conventions, such modules can be used at home as part of a larger layout or as stand-alone units.
The S-MOD system has been designed to meet the above objectives and several others. - Reversability - The physical and electrical standards allow for reversability of modules. The ability to reverse a module by turning it 180 degrees maximizes flexibility of use. - Design Flexibility - These standards do NOT include length, width, or corner standards in order to permit maximum design flexibility for the builder. There are however recommended practical size guidelines in the FAQ section of this site. - Flange size and rail height. - In “S”, as in other scales, there are a variety of wheel flange and rail heights in use. The standards do NOT specify rail size in order to permit flexibility for the builder. Trackwork built to NASG track standards S-3 will permit use of any rolling stock which has wheels and wheelsets which conform to NASG Wheel Standard S-4. The standards will also allow the use of American Flyer® and American Flyer® compatible (hi-rail) equipment provided that the rail is high enough (code 125 minimum) and closing frog switches are used. - Electrical Simplicity - The basic wiring diagram shown at this site is simple, yet allows the module to be used in any layout, from the simplest oval to the complex layouts seen at national conventions.