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Multi-Club Modular Setup Considerations

In early November, 1999, the topic of joining modules from different HO modular clubs came up in the rec.models.railroad Usenet newsgroup. Rails on Wheels member Fritz Milhaupt posted the following advice. Please note that the following does not necessarily represent the official policy of Rails on Wheels.

    [Our] club builds joint HO layouts with other clubs fairly regularly, including a four-club layout we set up at the NMRA National in Madison a few years back. Here are a few common sense observations, as a starting point:

    • I would avoid asking people to bring modules onesy-twosy. It's a lot easier to get things to work when you combine layouts from clubs-- that way you are likely to have to deal with fewer different interpretations of standards, and a lower number of wiring and trackwork peculiarities (especially if you need to make adapter harnesses to compensate for different types of electrical connectors). It's easier to deal with connecting entire sets of modules than with various modules from different clubs intermixed. The number of potentially problem-causing inter-club interfaces is reduced. It helped that we defined the interfaces between clubs as block boundaries.
    • Modules that have been run in club setups successfully are the ones you want to use. Multi-club setups are NOT the place for people to test new modules.
    • When dealing with clubs, it's a lot easier to contact the people involved and make sure they understand exactly which standards you are assuming. Most clubs have one or two guys who understand the track and electrical situations on their layout better than anyone else. These are the key people to have involved. They're the ones who can help decide which modules from their clubs are actually used, and which ones won't work well in the setup.

      For example, if you're running one mainline track under DCC, and the other under conventional DC/block control, you'll run into trouble if somebody tries to connect a module in place that common-rails both main lines to do two-track detection for grade crossing signals. Both ways of wiring are perfectly acceptable, but not when used together.

      Another situation I've seen regards trackwork. We thought we'd have no trouble running with another club's modules in the layout, since their minimum mainline radius was rather large, though not quite as large as ours. We run 54" minimum mainline radius, and they were running something like 42". What they didn't tell us was that there was a pair of 24" radius S-curves on one of the modules, on a shoo-fly which they had exempted from the 42" rule because it looked neat. Any time we tried to run a string of scale-length passenger cars through it, they would derail on those s-curves. Naturally, we didn't notice it until the show was under way.

    • It has to be made clear exactly what is expected in the way of trackwork and electrical specs. And these expectations MUST be enforced, if you want to run reliably. Hearing "Oh, didn't we tell you-- you have to shut off both mainlines before throwing that toggle switch" gets old in a hurry.
    • Be clear about definitions. Two people can say "Oh, our modules are wired conventionally," where one means that they use common-rail wiring between the mainlines, and another means that each mainline has an electrically-independent bus.
    • Visit the clubs and look at their modules before inviting the club. Pay careful attention to the trackwork, then ask fairly-detailed questions about the wiring. It also helps to mention the types of equipment your members run, and see whether anyone at the other club winces, or tells you that it won't work on their modules. Then you can decide whether to include the restricting modules, or exclude the offending equipment.
    • If you plan to use DCC on a modular layout in any scale, we recommend taking a look at the North Raleigh Model Railroad Club's Rules for DCC Design & Operation of NTRAK Layouts. While they use Digitrax, most of what they say applies to other systems as well.

Overhead view showing 2/3rds of the Michigan Modular Alliance layout at the 1998 train show at McMorran Place, in Port Huron, Michigan.

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