District In A Box

From the time of N-Land Pacific’s first public show in October of 2006 until our attendance at The Big Train Show in Ontario in the middle of 2010 the club grew from six modules to more than thirty. During that period we relied on a single DCC booster to power our layouts.

Our Digitrax DCS100 proved sufficient for the task, but we began to feel things might run better if we divided the layouts into multiple power districts. One of the major problems was that a short in any part of the layout would shut down the whole thing. Another was the increased use of sound equipped locomotives which could cause an additional strain on the single booster.

We found the answer in the Booster Farm concept developed by the NorCal Free-mo group. We built a wooden framework to contain the equipment in early 2011 and first used the Booster Farm at the Ontario show in June of that year. This centralized booster setup allowed us to divide our layouts into three to four districts and it worked well for us until early 2014.

At the Great Train Expo in Anaheim that January we set up our largest layout ever. It filled a space 50’ x 70’ and used more than sixty modules. We set up five power districts in the Booster Farm and attempted to include a Digitrax PM42 Quad Power Manager into the mix. It didn’t go well. We had many long periods without power in some districts and experienced a significant amount of frustration trying to track down the problems.

We felt that having all the boosters in a central location had worked well in the past, but it wasn’t going to work as our layouts grew larger. Moving the boosters out into the layout had been advocated and implemented with success by other modular groups. We decided to try decentralized power for our next layout and began working on a concept that one member dubbed a “District In A Box” (or DIAB).

Decentralizing the power districts in modular layouts is accomplished by gathering the DCC booster, its power supply, circuit breakers, LocoNet protection equipment (Digitrax LNRP or similar) and any monitoring devices desired into a portable package. AC power (110 volt) must also be supplied to the remote equipment. The Command Station is located centrally and the only connections needed between it and the DIABs are the DCC Common wire and the LocoNet cable carrying the DCC signals from the Command Station booster.

We constructed our DIABs out of ½” furniture grade plywood. Construction drawings are available here. The shape is basically a tray with high side panels and a central piece that incorporates a carry handle. There’s a cutout in the central piece to allow larger power supplies and wires to pass from front to back. The overall dimensions are 15” wide by 12” deep by 12” tall.

Our design was made to accommodate Digitrax equipment. The DCS100 (or DB150) sits in the front part of the tray with its power supply next to it extending into the rear part of the tray. After construction we found that it was easier to use the connectors on the front of the Digitrax booster if it was raised as high as the front lip of the tray. A small platform was made from a 3 ½” x 4 ½” piece of ½” plywood supported by two parallel strips of 1” x 4 ½” plywood. This left a channel 1 ½” x 4 ½” under the platform. The booster sits on this platform and a Velcro® strap is passed through the channel and around the booster holding it in place. In this position the booster is high enough for easy connections to be made.

The connected wires are secured to the tray base with plastic wire clamps or wire management staples and are directed through the opening to the back side of the tray. The front side of the central piece (containing the carry handle) is used to mount an LNRP LocoNet Repeater. There is room for a second panel device to be mounted in this location such as the inline amp/volt meter shown in the accompanying photos. The example DIAB in the photos also includes a New Rail Models throttle pocket on the front of the central piece.

The back side of the tray holds a four-outlet power strip. The back side of the central piece is where two DCC Specialties PSX-1 circuit breakers are mounted. The example DIAB also includes a PowerPax DCC programming booster that is used in conjunction with the Digitrax PR3 mounted near the LNRP above the DCC booster power supply. The PR3 and PowerPax booster are used by the owner of the example DIAB for sound decoder programming. The PR3 can also be used with a laptop computer and a router to create a WiFi train control system.

Many of the items shown in the photos are not required for the basic DIAB. A booster, power supply, power strip and circuit breakers are the minimal equipment. The Digitrax LNRP helps protect the Command Station from LocoNet problems and is highly recommended.

Wiring diagrams for the basic DIAB are linked below. One uses two PSX-1 circuit breakers and the other uses a Digitrax PM42 to provide four circuit breaker protected power outputs. Both use the Digitrax LNRP.

As noted above there are two connections required between each DIAB and the Command Station — the DCC Common and a LocoNet cable. In order to connect multiple DIABs to the Command Station booster we are using a LocoHub8 for the LocoNet connections and a terminal strip with one side shorted together for the DCC Common connections. See the accompanying photo.

The DIAB concept proved successful at The Big Train show in June 2014. We had five power districts in a rather complicated arrangement. The DCC setup went smoothly and there were only minor problems mainly due to wiring mistakes. We used it again a few months later at a smaller show without any problems whatsoever.

N-Land Pacific currently has six DIABs and a DCS240 Command Station. We anticipate these will fulfill our distributed power needs for the foreseeable future.

Click here for illustrations