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The Randall Museum in San Francisco hosts a large HO-scale model model railroad. Created by the Golden Gate Model Railroad Club starting in 1961, the layout was donated to the Museum in 2015. Since then I have started automatizing trains running on the layout. I am also the model railroad maintainer. This blog describes various updates on the Randall project and I maintain a separate blog for all my electronics not directly related to Randall.

2020-10-13 - Lodi & Fairfield

Category Randall

Here’s something nice: Jim is having a good time operating on the layout at Randall. You can read the details in his Train Orders post: SP Operations Today On Randall Museum Model Railroad.

I did spend some time cleanup the Napa yard, and making the Napa-mainline interchange more functional, and this is paying off.

Jim has also started using Lodi for switching. I’m really glad to learn that. First it’s a really neat part of the layout that is quite underused. Second I appreciate the use of it for switching operations, and not just running in a loop. Having operational variety is the whole point of a layout like the one designed at Randall.

That came with a request, which I fully support:

Make block B905 usable for switching near Lodi.

On the picture above, this is the “siding” just below that Alaska passenger train. It is actually the lead out of the Fairfield Industrial area into the mainline, which is called B905 on the track schematics below:

That block is controlled by Fairfield, which is itself totally disconnected right now (several shorts, etc.) and thus has no power. Since we do not currently use Fairfield, it would be nice for Jim to be able to spot some trains on that track.

Turnout T112 is functional and actually controlled on the Lodi panel, not on Fairfield.

A solution would be to fully isolate block B905 and power it up from T905 to block 110 from the mainline.

B905 is fairly long and I could also cut it in half and only power the half next to Lodi.

Since the layout is of common-rail design, there’s often continuity in one rail through the turnouts, and we need to isolate the block shortly after T905. The easiest way to do that is to create gaps on both rails, then either find existing track feeders or solder new ones, and power them directly from block B110.

This should be properly documented so that we can either reverse it later, or documented as the way it is done.

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