What is Free-mo?

Short for Free Modular, "Free-mo" is a standard that promotes high-fidelity prototypical appearance and operations for N scale modular railroading

The Free-mo N Standards

Free-moN attempts to raise the bar for N scale modular railroading by specifying standards for benchwork, track and digital control that promote and strongly encourage prototypical appearance. This document contains standards that must be followed to the letter along with recommendations, in italics, that have been gathered from various sources.

The Free-mo standard for N Scale has the following objectives in mind:

  • To promote and require high-fidelity prototypical scale model railroading.
  • To ensure reliable track and electrical operation.
  • To encourage visual continuity between modules.
  • To encourage a loose association among individuals free from club memberships, dues and titles.
  • To keep the standard specifications to a minimum without compromising the above objectives.

Each standard set forth below must satisfy all of these objectives.


Any component (or group of "sections") of benchwork that is meant to be operated as a single unit in a fixed configuration. A module can have any number of sections. The ends of a module must comply with the mechanical standards defined in the Framework description below.

A component of a module, complete with benchwork, track, scenery, etc. Except where otherwise noted, standards for module end interfaces do not apply to inter-section interfaces, as these are considered to be internal to the module.

The standardized end surfaces of a module, usually two, which join to another module.


Framework refers to a module's structural frame including end plates, legs, braces, decking, etc. Throughout this document common sense construction techniques should apply.

Endplates shall be constructed of 3/4 inch birch plywood or an equivalent material that resists warping and be 6 inches high and at minimum 12 inches wide. Module to module end plates shall be secured with C-clamps. Track alignment is accomplished by raising or lowering the module legs and manual side-to-side adjustments before clamps are tightened.

Legs and Bracing
Each module shall have legs that support the module by themselves except in the case of very short modules. Legs are constructed from 2x2 or 1x2 wood with cross bracing. Module height adjustment shall be accomplished by the use of Titus Leg Levelers. Nominal and minimum height of railhead from the floor shall be 50 inches. On modules with grades the maximum height of the railhead shall be 62 inches above the floor and the elevation of the high end shall be some multiple of 3/4 inch above the low end.

Sub-roadbed surface shall be sturdy enough to prevent sagging over the length of the module. For modules of framework up to 2'x4', supporting at least 2 evenly spaced crossmembers, 1-inch thick extruded foam panels has proven sufficent. 2 inch foam shall be used on modules with framework over 2'4'. Plywood can be used for the scenery base instead of foam if the modeler desires, but using foam can help reduce the weight of the module. Before track is laid, cork roadbed shall be placed between the sub roadbed and track.

Each side of a module shall have a fascia that fully covers the side. The preferred fasciae material is 1/4 luaun plywood. The top edge of the fascia shall be contoured to match the scenic topography of the module. All fascia shall be painted with flat black, satin, or equivalent paint. The color is to be continued onto the endplates a distance of one inch.

Free-moNebraska uses full uncut rolls of 48 inch wide black broadcloth. It is applied in a continuous skirt to all modules after set up using clothes pins or spring clamps to pinch the cloth to the bottom of the fascia. Skirting is applied to both sides of the entire layout.

Track and Ballast
Mainline track shall be code-55 nickel-silver flex or code-55 sectional track. All wooden ties and rails will be painted Rail Brown (Floquil F130007, or equivalent) and ballasted. Ballast color shall match the prototype of the module using Arizona Rock and Mineral or equivilant real rock ballast. Woodland Scenic ballast is strongly discouraged.
Minimum radius for the main line and related tracks such as passing sidings shall be 22 inches with at least 6 inches of straight track between reverse curves. 18" minimum radius may be used on all other applications. Main line turnouts shall be at least #7 with #10 used for cross-over switches.
Mainline maximum grade shall be 1.5 percent. Main line roadbed must be 1/8 inch cork or equivalent. At the endplates the track shall be centered perpendicular to the end, straight and level for at least 3 inches from the outside face of the endplate. Ballast shall be continued to the module end for good appearance and matching with the adjacent module whenever possible.
All modules shall use the "Butt Joint" method of intermodule track alignment where track and ties are laid to the end of the module and secured using glue, or a strong mechanical connection. Track ends are squared and flush with the endplate face. Vertical and horizontal track alignment is accomplished visually before the endplates of adjacent modules are secured together.
In order to allow joining the modules of the other major Free-moN groups around the country, we have adopted a double track mainline spacing of 1.125", where each track center will be offset .5625" from the module endplate center.

Wiring and Electrical
Free-mo N will use Digital Command Control. We use four power districts (District In A Box) with the LocoNet connected to a command station. Throttles are the responsibility of individual members. Members may upgrade to radio when this system is in place or continue to use tethered/IR throttles.

Track Bus wire shall be 12 gauge (stranded preferred) spanning the length of the module between the endplates. Track feeder shall be 20 to 24 gauge wires. The Track Bus wires shall terminate near the center of the endplates, extending long enough to attach to the adjoining module with a pair of 30 Amp Anderson Powerpole connectors stacked vertically (hood up, tongue down). The top Powerpole shall connect to the left rail as you face the endplate, the bottom Powerpole shall connect to the right rail. Following this standard, exactly as it is stated, will make set up time quicker and foolproof.

A pair of red connectors will be used to distinguish them from those used for the Accessory bus (if used).
All track connections/joiners should be soldered. If track sections and/or turnouts, are not soldered together then section(s) and turnout(s) must be physically connected to track bus by means of track feeders. It is the responsibility of the module builder/owner to ensure dead spots do not exist on the module.

AC Accessory Buss wire shall be 12 gauge wires spanning the length of the module between the endplates. Accessory Buss wires shall terminate near the center of the endplate(s), extending long enough to attach to the adjoining module, with a pair of 30 Amp Anderson Powerpole connectors stacked horizontally (tongue-to-tongue, hood-to-hood). A pair of black connectors will be used to distinguish them from those used for the track buss. This two wire buss is used to power turnout motors that control track switches but it may also be used to power other accessories on modules such as structure lighting, signals, animation, and the like.


Turnout frog, points, and point rails shall be powered in a manner that does not rely solely on the contact between the points and the stock rails.

Mainline turnout control will be by fascia mounted push/pull cables to operate New Rail Models Blue Point or Bull Frog turnout controllers. Sidings or branch lines can be manually operated using Caboose Industries ground throws. Some sort of positive locking of the switch points is recommended. Although Micro Engineering turnouts have this feature, the NLP standard is Atlas code-55 turnouts. Hand-laid code 55 turnouts may also be used for special situations.

Many members have found the New Rail Models Blue Point turnout controller to be a satisfactory method for locking switch points and correctly powering the frog. A Circuitron Tortoise switch machine or Tam Valley servo and power accessories can also be used, but most of our modules do not have an accessory power bus with DC power, so a power source would have to be available for a module using this type of turnout controller.

Hand-laid turnouts are acceptable, providing they operate consistently without glitches and are flawless in rail height consistency, tie spacing, and follow the track and ballast coloring standards. All hand-laid turnouts must be tested and proven operationally sound before being used at shows and/or our Open House. Where lights (whether signal head or fascia mounted) are used to indicate the position of a turnout, 2 lights shall be utilized, with green over red indicating the switch is lined for straight track, and red over green for switches lined for the diverging route.



The NLP utilizes Digitrax control in various configurations, based on the needs or demands of the layout. Any Digitrax throttle may be utilized and a fully charged 9-volt battery is recommended in all throttles. Smart phone throttles may be utilized when a Wi-Fi JMRI system is employed. (Refer to the Operations Manual for further details).

Each member is expected to own and be responsible for their throttle(s). Members are currently using the following throttle models: UT4, UT4R, DT100, DT400, DT402, DT402D and DT402R.


Each loco shall be equipped with a Digitrax compatible decoder. Locomotives with default addresses will be allowed ONLY on the dedicated programming tracks. Analog stretching is disabled in the command station; therefore, all decoders shall have CV29 configured with Analog Mode Conversion = OFF. (Refer to the Operations Manual for further details).


The NLP has decided each member will have a unique two-digit member roster prefix. When programming loco addresses, the first two digits of the road number will be replaced with the assigned two-digit member roster prefix. If a member's assignment prefix is 66 and the road number is 4449, member A would program the decoder in 4449 to 6649. This methodology allows multiple engineers to operate the same road number with no DCC addressing conflicts. (Refer to the Operations Manual for further details).

LocoNet Buss

Each module shall have a single 6-wire "RJ12" phone jack mounted on the underside at the end plate, to connect the LocoNet between modules.

TIP: mount a female-female straight-through-wired RJ12 coupler inside each endplate of the module, attached with either glue or Velcro.

Modules four feet or longer shall have Digitrax UP5 or UR90 utility panel/receivers mounted on each side of the module for hand-held DCC throttle connection. When using Digitrax UP5/URxx utility panels/receivers, ensure the track status terminals are connected to Rail A and Rail B.

Intermodule connection is achieved with a simple 6-wire RJ12 cord. All of the LocoNet connections require straight-through cables. Standard telephone cables are not wired straight through. Use color-coded wire matching the wire colors present in the jacks (white/green/yellow/black/red/blue is most common). Use minimum 26 gauge solid core wire for sturdy connection to jack screw terminals. Add strain relief to the wires near their connections to the jacks.

The mainline shall be ballasted and some form of scenery is needed to hide the benchwork. Scenery for the first 3 inches at the end plates shall have a flat profile roughly 1/4 inch below the top of the main line rail.

Landscaping along the module ends must be designed to flow smoothly into adjacent modules - avoid features such as roads, lakes, and so forth from running against the module ends. Use a generic grassy/sandy terrain.

The group has set Delta’s Ceramcoat “trail tan” acrylic paint as the standard base color. The scenery base color should continue onto the endplate from the top of the module a distance of one inch. Our scenery is desert or semi-arid Southern California with sandy soil and low bushes or other vegetation as appropriate for the scene being modeled. Rocky hills and dry washes are appropriate for our scenery standard. Modeling of an actual location is encouraged.


Rolling stock wheels, trucks and weight shall meet or exceed NMRA Standards and Recommended Practices.

Atlas code-55 track is known to cause problems when rolling stock uses wheel sets with excessive flange depth (“pizza cutters”). It is recommended that rolling stock used on NLP modules have low-profile flanged wheels, plastic or metal, installed to prevent derailments and other problems.

Revision History
  • Rev 1, 14 Aug 2002, Initial Revision.
  • Rev 2, 12 Sep 2002, Upgraded track bus wiring minimums to meet DCC requirements.
  • Rev 3, 30 Jul 2003, Increased feeder wire minimum from 22 to 24 gauge. Increased rail setback from 1/2 inch to 3/4 inch.
  • Rev 4, 08 Nov 2005, Powered frogs. Simplification and clarification. Anderson Powerpole bus connectors.
  • Rev 5, 13 Apr 2011, Revisions to N-Land Pacific practices and DCC.
  • Rev 6, 20 Apr 2011, Add all track shall be weathered.
  • Rev 7, 12 Oct 2012, Add DCC loco addressing standards.
  • Rev 8, 27 Jul 2013, Add track and ballast refinement specification for 1:1 scenes as well as defining the modeling area of Southern California

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