Modeling The San Antonio and Aransas Pass Railway - Control System


In the Real World, I'm a controls systems engineer, so I kinda get into this stuff in a low-key way. No signaling system yet or turnout control yet, but I think about it.

I'm using a Lenz set 02/4 DCC system, which isn't the fanciest one out there, but it does everything I need and is on the lower end of the price spectrum. (All I wanted was a big-knob controller, 4-digit addressing, ops mode programming, and 128 speed steps - and if this is all Greek to you, check out Tony's Train Exchange or the NMRA sites. And don't look for the 02/4, as it's no longer manufactured.

Wiring is 16-gauge stranded from the power supply (an 8-amp MRC) to the booster, and 18-gauge from there to terminal strips mounted under the layout. 18-gauge is arguably too small, but I don't plan on running any multi-unit lashups, so I think it'll be okay.

Drops from the rail to the terminal strips are 20-gauge solid wire. One side of the terminal strip is used for feed, the other for drops. Jumper bars (from Radio Shack) are used where possible. All wires have crimp-on spade lugs. I prefer terminal strips to spliced, soldered, or 'suitcase' (insulation displacment) connections.

Place your strips near the front edge of the layout and they're a lot easier to work on. I keep them in place with double-sided foam tape.


DCC Locomotive Installation Guides

IHC 2-6-0 Mogul

The IHC American is virtually identical. I haven't wired the headlamp to a function output, so it's on whenever the track is powered.

Decoders I've used so far include the Lenz 103XF and 104XF. Both are installed in IHC locomotives and have not given me any trouble.


Operations

There's not a lot to operations yet, so it goes here. Functionally, I have a town with hidden staging yards off each end. Schematically, I have a loop with a town and a yard on it. Anything eastbound is heading to Yoakum, and anything westbound is heading toward Lockhart (via Gonzales and Luling.)

Yoakum is where the SAAP shops were located, and provides access to the main Houston - San Antonio route, and the northbound line to Waco.

Lockhart had an interchange with the MKT, providing access to Austin and a shorter route to Dallas. In the early 1920's, oil was discovered near Luling, which presumably generated a lot of traffic.

I spent a lot of time trying to find a switchlist program that would work well for small, basically single-town layouts. Most importantly, it had to run under MacOS 8.6. I even learned Perl to write my own, but ended up creating a MS-Excel spreadsheet that does the job. It can be found here (34KB - download it, don't just open it.) I've included sample data on the 'Data' tab. Basically, list your cars and all valid destinations for each one. One will be the 'home' destination, to which it will return after each trip. In my case, these are generic 'points East' or 'points West'.

Feel free to distribute or modify the code as you see fit, as long as the text in the 'Disclaimer' tab is left unmodified. That would be a good place to put notes, if you're so inclined. Heck, I'm not even sure what versions of Excel work with it. Office 2000 on Mac 8.6 and Excel 2003 on Windows 2000 both seem to be okay.


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Last updated 06 October 2005