MARRS HO Module Standards

Basic Module Standards

NMRA Compliance

Except as explicitly described below, MARRS HO modules shall be built in conformance to these applicable NMRA Standards and Recommended Practices (RPs):

• MS-1.0, Module Standards, Standard Gauges
• MRP-1.3, Recommended Practices, Standard Gauges, Modules
• MS-1.3, Electrical Standards for Modules, All Scales
• MRP-1.3, Electrical Recommended Practices, All Scales, Modules

Exceptions to MS-1.3 and MRP-1.3

Minimum wire gauge for track power shall be 12 gauge for all mainline power, except for track power leads/drops under one foot in length which may be as small as 22 gauge.

Instead of Cinch-Jones connectors, 30-amp Anderson PowerPole connectors will be used. (For a detailed description of PowerPole connectors and associated terminology, see the Appendix.)

Black connectors will be used for the front rail of each mainline track, and red connectors will be used for the rear rail of each mainline track. ("Front" is defined as the normal viewing side of the module.)

At the right end of the module (as viewed from the front), the connectors for each mainline track will be paired black-over-red. At the left end of the module, this will be reversed, with the connectors being paired red-over-black.

No wiring carrying 110V power is permitted on the module.

Scenery Recommendations

Paint the sides of the rail before ballasting. Prototype rails are rusty rather than shiny. Floquil Grimy Black and/or Rail Brown are appropriate.

Although the plastic crossties of prefab track will eventually collect a coat of dust and become less shiny, it is recommended that they be painted before ballasting. Floquil Grimy Black mixed with varying amounts of Roof Brown will resemble creosoted ties of varying ages.

Use Woodland Scenics Gray ballast on Main tracks, Woodland Scenics Cinders on sidings.

Other considerations being equal, use Woodland Scenics Green Blend ground foam for the basic grassy cover.

Appendix: Anderson PowerPoles

Red and black PowerPole shells, and a contact wiper. Note the "hood" and "peg" on each shell.

An Anderson PowerPole connector is a single-conductor connector, made up of a metal contact wiper surrounded by a plastic shell. The shells are available in various colors.

Each connector has a C-shaped "hood" and a rectangular "peg" molded into it. By convention, the hood is the "top" of the connector and the peg is the "bottom." An electrical connection is made by turning one PowerPole upside-down relative to another and pushing them together end-to-end; therefore, there are no "male" or "female" PowerPoles.

PowerPole connectors are available in different amperage ratings, based on the size of wire they are designed to accept. For example, 15-amp PowerPoles accept 18-22 gauge wire; 30-amp PowerPoles accept 12-16 gauge wire. The 15-, 30-, and 45-amp versions use the same shell, and can be freely intermixed. Higher-rated connectors are progressively larger, and cannot be intermixed.

PowerPoles joined "red over black." Note the hood and peg positions.

The connectors are keyed so that they may be interlocked, either vertically or horizontally, to form multi-connector "blocks." For connectors joined vertically, they may be described as being one "over" the other. For example, a pair of PowerPoles "joined red over black" would refer to a red connector, attached to the top of a black connector. (Please note that "over" refers only to how the connectors are joined to each other. If a "red over black" pair is turned upside down as a unit, it's still a "red over black" pair.)

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