One of the ‘new’ ideas I discovered, on returning to railway modelling after a twenty year break, is DCC. This is attractive to me for two reasons; firstly I can drive locomotives not blocks of track, and secondly because it holds out the hope of controlling points, signals etc. from a computer.

I have a Dapol 9f which is entirely inappropriate for the branch to Belsey, but comes with a DCC socket and an opportunity to try DCC out. In order to help decide which system to buy I used my good friend Google to research the various systems available.

The most cost effective way to begin with DCC is to buy a ‘starter’ set. This is usually a unit which combines the power control, command station and throttle functionality into one piece of equipment (although some also include a hand held throttle). What I wanted was a starter set which I could use to control Belsey with, yet which would still be useful when I expanded the layout to include Marsalt Gill. I joined the Yahoo DCC mailing list (http://dir.groups.yahoo.com/group/DCC4EVERYONE/) to see what success stories and abject failures people were experiencing and whittled the list down to the following:

· Lenz Set 100 (http://www.lenz.com/products/index.htm)

· Gaugemaster Prodigy Advance 2 (http://www.gaugemaster.com/gmdigital.html)

· Digitrax Zephyr (http://www.digitrax.com/prd_zep_basic_set.php)

· NCE Powercab

Each of these is a ‘starter sets’ which would meet my requirements for running Belsey, and could be expanded by adding further power controllers. However only two of these manufacturers offer an extensive range of accessories and expansion units; Lenz and Digitrax. This turns out to be unsurprising as these two manufacturers are the designers of the two predominant DCC network protocols available today, Lenz with their XpressNet protocol, and Digitrax with their protocol, LocoNet.

These two protocols define how DCC units communicate with each, not the nature of DCC decoders which live in the locomotives. The DCC ‘network’ protocol is particularly important in computer control situations, and since my long turn goal was to write my own computer control software I researched the details of XpressNet and LocoNet. This is technical stuff, down to transmission of data packets onto the bus and the command and response protocol between control units.

If you never intend to write software then there is no reason why you need to know, nor care about this stuff. However after reading the technical specifications I came to the conclusion that I preferred the LocoNet implementation. LocoNet is also supported by other manufacturers including Fleischmann (http://www.fleischmann.co.uk/), CML Electronics (http://www.cmlelectronics.co.uk/) and RR-Cirkits (http://rr-cirkits.com/) to name the vendors I’ve purchased from.

My modelling buddy Alan Powell is a fan of all things Fleischmann (except their painful points) so I tried out his Fleischmann Twin Centre controller. I’d installed a copy of JRMI (http://jmri.sourceforge.net/) on my laptop, a bunch of open source DCC applications available for Windows, Linux and OSX. One of the tools in JRMI allows you to monitor in real time the commands whizzing up and down the LocoNet bus, so I was able to see the protocol in action which confirmed my understanding of the capabilities of the system.

I visited an exhibition to get with the aim of trying out the Digitrax Zephyr. A very patient gentleman from Ron Lines of Southampton (http://www.ronlines.co.uk/) allowed me to play with one, even fitting a Digitax decoder into my 9F and allowing me to drive for a while on a single piece of flexi track. I bought the Zephyr and three decoders there and then, and have bought more decoders from the same source since (I have no connection with Ron Lines other than being a satisfied customer.) including ‘hard wire’ decoders for conversion of non-DCC ready locomotives. How I undertook my first DCC conversion is a story for another time, but it is a very satisfying achievement.