Alton Model Railway Group

Bringing DCC to Group Layouts

Pine Bluffs and Ceda Falls

AMRG’s ‘American Section’ decided that Pine Bluffs Freight Yard (the next phase of its Pine Bluffs and Ceda Falls exhibition layout) would be DCC operated from the outset. Digitrax equipment (Super Chief) was chosen as this was already in use by a number of the section members, thereby giving us access to additional controllers when required.

Whilst the layout is not large (at least in US terms) with a run of around 24feet we decided to adopt a ‘belt and braces’ approach to the installation. We employed a split power bus using two PSX1 breaker boards from DCC Specialties with one feeding the track and the other the accessories. The major advantage with this approach is that in the event of a track short circuit caused by trying to drive a loco through an incorrectly set turnout (which is very much easier to accomplish with DCC) the power to the accessory bus is not affected. This enables the point to be re-set without ‘the hand of God’ being employed to move the loco clear of the turnout. We fitted the Digitrax Super Chief, its power supply and PSX1 boards in a plastic storage box (obtained from Hobby Craft) to make storage and transportation easier (see picture). Connection from this unit to the layout is by a ‘standard’ 4 way terminal block/connector (located in the bottom right of the picture. This same connector type was used with short ‘jumper’ cables to connect the baseboards together.

Due to the greater impact voltage drop can have on DCC operation rather than depend on the conductivity of the track we ran a track bus and accessory bus under all of the baseboards. For these we used solid core 1.5mm house wiring cable. We ensured that for each piece of track or turnout we ran a dropper wire from each rail to an under-board tag strip. I am not sure we would use tag strips again it is probably as easy and less messy soldering the droppers directly to the bus wire; however things work acceptably. One point worth noting is that a ‘standard’ 25 watt soldering iron produces insufficient heat to ensure a good soldered joint with the large amount of copper in 1.5mm solid core wire. We eventually used two 25 watt irons to ensure the multiple connections on the tag strip were secure and this was with lead based solder, the new ‘lead free’ variety has a higher melting point so more heat would be required.

The next phase of the process is to take Pine Bluffs Depot off the exhibition circuit and convert it to DCC so that the two layouts can be operated in combination.

Alton

The ‘Alton Section’ decided to convert their OO Gauge layout of Alton Station in the present era to DCC operation in 2012. They chose to adopt Digitrax equipment from a commonality standpoint as this was already being used by the Group’s ‘American Section’ and a number of the group members.

The conversion to DCC was relatively straightforward, despite the misgivings of a number of members and was completed in around a month of occasional evenings. It was decided to remove the ’cab control’ section switches because although these could have all been set to the same section there would always be the possibility of an operator inadvertently changing one of the switches. A number of additional dropper wires were added so as to ensure a good connection to the bus which had been added and to remove the dependency on conductivity of the rail and its joiners.

An aspect worth consideration is the conversion of the locomotive stable. With a club layout such as Alton where all the stock is owned by individual members this requires a commitment from everyone (or at least a majority) to ‘chip’ their locomotives, a both time consuming and not inexpensive activity.