Poway Station All Scale Modular Railroad Club (Poway Station) subscribes to all National Model Railroad Association (NMRA) Standards and Recommended Practices (RPs) with specific exceptions and additions. NMRA Standards and RPs have not been reproduced here, but are available at the NMRA web page, http://www.nmra.org/standards/ . Printed copies of the NMRA Standards and RPs will be available for review at most Poway Station club meetings. It should be noted that the NMRA has recently proposed revisions to its Standards and RPs. This document has not been evaluated against the proposals.

In addition, the majority of our standards are based on the Ntrak Standards, developed by Ntrak, Inc., and published in the Ntrak How to Book, a copy of which is available for review at most Poway Station club meetings.

At this time these standards apply to HO and N scales only, unless otherwise noted.


1. These Standards are required only for common-use tracks. Tracks 1 and 2 for HO, Tracks 1, 2, and 3 for N). They are recommended (but not required) for other trackage.
2. For reference, each module has a front (the viewing side) a back (the skyboard side) and a left and right end, when viewed from the front. Refer to the module diagram in the National Model Railroad Association (NMRA) Introduction to Module Standards and Recommended Practices, on the Internet at http://www.nmra.org/standards/ms_intro.html.
3. The mainline closest to the front at the module frontier shall be Track 1. The next track towards the rear shall be Track 2 etc. If there is a siding between the first mainline and the viewing edge of the module, it shall be referred to as Track 0.


a. Wiring harnesses consist of at least # 16 gauge stranded wire. The wire in the harnesses (buss) shall be color coded as per Table 1, below.
b. Cinch Jones, series 300, two pin, plugs and sockets (or compatible) are used to connect the harnesses from module to module.
1). Cinch Jones, series 300, two pin, cable clamp (male) plug (p/n P-302-CCT) on the right side of the module. A minimum pigtail of twelve inches must be provided below the module edge on the (male) right end.

2) Cinch Jones, series 300, two pin, panel mount (female) socket (p/n S-302-AB) or Cinch Jones, series 300, two pin cable mount (female) socket (p/n S-302-CCT) on the left side of the module. A minimum pigtail of six inches must be provided below the module edge on the (female) left end if using the cable mount socket. If using a panel mount socket, see Recommended Practice II.B.1. below.
c. For each connector and the track associated with it, wiring shall be consistent among modules to provide electrical continuity.
1) the wide plug/socket shall be connected to the rail closest to the front of the module,
2) the narrow plug/socket shall be connected to the rail closest to the back of the module.

3) for the DC buss (White/Black line)
a) the white wire shall be connected to the wide plug/socket, and carry the positive (+ DC)
b) the black wire shall be connected to the narrow plug/socket, and carry the negative (- DC)
d. Both male and female connector ends shall be colored for easy identification and connection during set up.
1) Main track1 shall be RED
2) Main track 2 shall be YELLOW
3) Main track 3 (for N scale) shall be BLUE

4) Local tracks shall be orange or green (or other colors as needed, provided they do not conflict with colors already assigned)

5) DC buss (if used) shall be white.

Coloring may be effected by painting or wrapping appropriately colored tape around connectors.
e. The wiring harnesses shall have a barrier type terminal strip mounted near the center of the module, for connecting the buss to the feeder wires.
f. Feeder wires (20 to 24 gage wire) shall be soldered to the track and connected to the buss at the barrier terminal strip.

Track/Rail Gauge Color HO N
1 front 16 Red Main 1 Red
Line Main 1
1 rear 16 Brown
2 front 16 Yellow Main 2 Yellow
Line Main 2
2 rear 16 Violet
3 front 16 Blue Optional Blue
Line Main 3
3 rear 16 Gray
0/4 front/local 16 Orange Optional Optional
0/4 rear/local 16 Green
Optional use 16 White Optional Required
Optional use 16 Black
Table 1


1. NMRA Electrical Standard S-9 shall apply for ALL scales.
2. On all electrical connections use Rosin-core solder ONLY.
3. All rail joiners shall be soldered, or the rail joint shall be connected with jumpers soldered to each rail.
4. No section of common-use track shall depend on power being fed through bridge track.
5. All non-common-use (local) trackage shall be electrically-isolated from common-use trackage and be able to operate under its own power.
6. Powering of local tracks, switch machines, building lights, etc is the responsibility of the individual builder. A separate power source must be provided.


1. No air gaps are allowed: either use insulated rail joiners or other insulating material.
2. Both common-use rails shall be gapped at the following locations (there is no NMRA standard).
• Between turnouts located frog-to-frog
• Between turnout frogs in opposite rails
• Between turnouts when frogs in same rail
• Gap behind turnouts for independent control of power to siding and at each end of double-ended sidings
• Gap a scissors crossover at eight places: all rails between points, frogs, and at crossing
3. Feed power from point ends of turnouts
4. Feed power from middle of common trackage without turnouts



1. If using the panel mount socket. a metal bracket should be fabricated that will fasten to the module and hold the connector. (The club has a limited number of these brackets, having three holes, available for sale. We are attempting to locate a source for replacements, with provision for more holes.)
2. Fork type terminal connections are recommended to connect the harnesses to the barrier strip.
3. Harnesses and feeder wires should be supported on each module. Use "P" clips, insulated staples, or other suitable hanger.
4. Harnesses (and other wiring, if present) should be bundled using zip ties or other suitable binders.
5. Local power should not be drawn from the DC (White/Black) buss. The buss, if present, should be reserved for future use in powering throttles and block detectors. Existing modules that do not currently comply with this Recommended Practice are automatically granted an exemption until such time as the scale group develops the block detection system for your scale.

1. Wire for feeders should be stranded

1. Location of gaps before (in the direction of the points) turnout frogs should allow a minimum distance between the gap and the points to accommodate the longest locomotive that will be operated through the turnout, and a distance to accommodate the locomotive and at least one car is preferred.