Important note - while the standards below are accurate for the NWTM, they are presently incomplete and no longer comply with the standards set by the NMRA for NMRA HO modules. The standards have been changed by the NMRA since we adopted those described below. They were compliant when created and do match those of many groups who adopted the same before or prior to us doing so. It is yet to be determined as to if and how we will respond to these changes.



One of two standards used by the club is described by the National Model Railroad Association NMRA in their standards and practices for Standard Gauge Modules. Some of the NMRA standards have been modified to more closely follow our preferences and restrictions, but the modules done in this format will generally interconnect with standard NMRA modules.

Benchwork:

• Module length shall be an even multiple of 2'-0".
• Module interface ends shall be a minimum width of 24" and a maximum width of 36". The ends should be constructed with 1"x4" lumber as C-clamps will be the normal means of connecting modules.
• Height from floor to top of rail is 40", and there must be a height adjustment range of ±1" provided for in all legs.
• The module must be able to stand alone, and should have at least four legs.
• Roadbed will be mounted on plywood, homasote, or other rigid and durable material, braced to prevent sag or flexing.
• All exposed edges of a module should be finished for appearance, as all sides are likely to be visible.

Track

• Two standard gauge mainline through tracks are required. Club owned modules will use Code 83 nickel-silver rail for their mainlines and is the preferred code for member's modules.(note1)
• Interface track centerlines will be 5" and 7" from the front edge of the module. The mainlines will be perpendicular to the end and will run straight and level for a minimum 6" from the end. (note 2)
• Rail will be cut 1" from the modules end, but ties, ballast, and roadbed will continue to the module's edge. A 2" piece of Code 83 rail with sliding rail joiners will be used between adjacent modules to connect the rails. (note 3)
• MINIMUM radius of mainline curves is 36", with at least 12" of straight track between reverse curves. Transition curves are recommended to ease long cars in and out of curves.
• Grades in the mainline are permissible and are limited to 2.0% maximum. Track must enter and exit a module or module set at a height of 40" for a net change in height of 0".
• Vertical curves (changes in grade) on the mainline must be appropriate for operation of long vehicles. Superelevation (banked curve) is not recommended.
• Turnouts (switches) on the mainline shall have #6 frogs or larger. All mainline switches and turnout controls should be clearly marked so that they can be operated in the module owner's absence.
• Both rails of both mainlines will be electrically isolated from all other trackage on the module. Crossovers between mainlines shall have both rails gapped. Isolation gaps will be filled with an appropriate nonconductive material. No air gaps are allowed.
• For reliability reasons, sectional track and hand laid track are not recommended. Members who are skilled at hand laying track are not discouraged from using hand laid track, but should use their discretion as to where and when its use is appropriate.
  • a.) AZ Rock & Mineral's "Northern Pacific #130-1
  • b.) a 50-50 mix of Woodland Scenic's "Light Gray, Fine #785-74" and "Gray, Fine #785-75"
• Uncoupling ramps in the mainline should be electric or, if permanent magnet type, mounted to drop away or be easily removed.
• Powering of switch machines, building lights, etc., is the responsibility of the individual builder and should be separate from circuits which interface with other modules in a layout.
• Any trackage that is NOT mainline is not covered by NMRA Module Standards and is left to the discretion of the individual or group.

Wiring

• Wire used for power distribution in the mainline shall be #14 awg stranded or larger. Feeder wires shall be #24 awg or larger. Distribution wire will be firmly attached beneath the module and should terminate at each end in a terminal block.
• These terminal blocks will also retain a pair of two conductor Cinch-Jones type connectors, one male and one female. The male connector is connected to the right-side mainline, regardless of which interface end is being viewed. The wide blade is connected to the rail on the right of that mainline and the small blade is connected to the rail on the left of the same mainline. A female connector is connected to the left-side mainline. The wide socket is connected to the rail onthe left of that mainline and the small socket is connected to the rail on the right of the same mainline.

Right Side View
Left Side View

Footnotes:

note #1: The NMRA standard for Mainline track is Code 100. The use of Code 100 is permissible on NWTM modules as long as that module's owner provides for connection to adjacent modules with Code 83 track and/or Code 100 track.
note #2: The NMRA standard specifies that the minimum distance from the edge of the module to the first deviation in mainline (a switch, curve, crossover, etc.) shall be 7-1/2".
note #3: The NMRA standard specifies track (rail, ballast, and roadbed) setback from the interface edges will be 4-1/2". If this standard is followed then the module owner will provide TWO styles of bridge connectors:

• A bridge connector that has 4-1/2" of it's length comprised of roadbed, ties, track, and ballast and an additional 1" that is RAIL only. This will be used to connect to modules with a 1" setback to one with a 4-1/2" setback.
• A bridge connector 9" in length that includes roadbed, ties, track, and ballast for the complete length of the bridge. This will be used where adjacent modules both have a 4-1/2" setback.

(back to Track)