Layout Control

Layout control is a very broad term. At the most basic, it can refer to a simple DC “power pack” throttle used to drive an individual train. At the other extreme, it can refer to sophisticated computer-driven automation systems that will drive the train for you without any attention at all. Which doesn’t sound like much fun, really.

This section strikes a middle ground, covering electrical systems that allow various aspects of a layout to be controlled, such as track turnouts (switches), lineside signaling, train detection, crossing gate operation, etc. Much of this is interwoven with DCC, but I’m not going to cover direct use of DCC on the train itself (DCC decoders), as that’s already well covered in the DCC for Model Trains section of Model Trains. Individual pages here will cover different topics under that broad heading. The purpose is to provide a survey of the kinds of systems I’m likely to use on layouts. I won’t claim it’s exhaustive, but I am trying to cover a broad range, so I can be sure that when I make a selection I’ve covered all of the options likely to interest me.

While “layout control” may sound like a daunting topic to many modelers, it can be done with off-the-shelf components if you choose the right system, and if so the electrical work is no more complex than that used for block wiring a layout or DCC. It can also sound unnecessary (“I run my trains, not some computer!”), but it’s not about having a computer run trains, although these control systems can enable that if taken all the way. What it’s about is doing ordinary things like throwing a turnout or having crossing gates react to trains, with less effort and wiring. My goals do include automating some things, but mostly I just want to simplify the wiring of a fairly large layout without excessive work on my part.

A control system is complex, and requires thought in advance. It’s not something you’d do for a short-lived layout or a module in some larger modular club layout (although the designers of the club layout might want to specify use of a control system). But on a big layout, done well, one will pay dividends of time and reliability.

There are several broad categories that make up this topic:

- DCC itself (a general overview)
- Using DCC to control non-train devices (accessory decoders)
- Having trains report information back (decoder transmission)
- Using a bi-directional “control bus” (or separate cab and feedback busses) to both control devices and get information about them
- Supporting circuits and systems (detection, signal drivers, etc).

Note that a control bus (or its more primitive cousins cab and feedback busses) can be used completely without DCC, and these precede the development of DCC.