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Reply to "Colorado O Scale St. Vrain River Bridge Project"

AGHRMatt posted:

Erik:

Do you have any photos of the framing under the foam in the bridge module set? I'm curious how the foam is supported.

I responded to John for you he will likely show you what's involved in the design. 

This is from his article about the engineering earlier last year:

Lightweight Module Construction

A little history here will explain why this type of module construction came to be. Forty years ago N Trak was breaking a lot of new ground with the idea of modular layouts. They could be set up and displayed in many venues previously unavailable, like shopping malls. The hobby shop with the layout in the front window was getting rare and shopping malls were the the new meccas of retail trade. A lot of modeler got their start with these groups.

My club at the time was building a HO layout based on Marin County railroads in an old dairy barn. We decided to build a modular layout to display at the county fair. Construction was based on the N Trak standards, 1x4s with 1/2” plywood top. Sturdy but not very light. Legs were an issue as it was difficult to prevent swaying when they were leaned upon without getting involved with a lot of bracing. I even drilled lightning holes in th 1x4 crossmembers (actually 1/2”x4” plywood) in an effort to cut some weight. Later the 2x2” legs were replaced with 3/4” EMT conduit with angle braces to improve stability. Both efforts were marginal improvements.

My next effort was based on 1/4” plywood. Sides and ends were laminated with extra plys where the strength was needed. Legs were folding 2x2s. Not bad, it was lighter and easier to set up but still not quite right.

With my move to Colorado and switching to 1/4” scale came the opportunity to start over. Everything module effort to date had multiple toos problems:
too heavy
too fragile
too difficult to set up

Experimenting with a portable F scale layout introduced some new ideas. First to go was the legs, simple sawhorses under the joints replaced attached legs. Set up time was dramatically reduced. Next to go was the bolts/C clamps tyeing the modules together.

 

 

 

 

OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

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