Power Districts using DCC Specialties’ PSX

Here’s the second major thing I did this summer. So far, I’ve had a single power district for the ENTIRE LAYOUT. It’s honestly worked pretty well, but now that I have operations going, I’d rather have someone running through a switch the wrong way shut the whole layout down.

After a lot of decision making, I decided to upgrade to solid state protection. It works much faster than a mechanical relay (think of the Digitrax AR-1 reverser, or the PM42. They work very well, but it’s not an immediate shutoff.

The products I chose are the DCC Specialties PSX and OG-AR. The PSX series is probably the best breaker you can get – status LEDs, programmable with your DCC system, option to wire in a buzzer, and adjustable trip current. The last one was very important to me, as I don’t need the full 5 amps of my system flowing through one breaker to tell me there’s a problem! The OG-AR is part of the On Guard series. It’s not very well known, but it’s also solid state. The trip current is not adjustable, and you can’t control it through your DCC system. However, with 3 reversing sections that aren’t very long, I felt it was a good fit.

I decided to divide my layout up into 7 districts – 4 normal, 3 reversing.

  1. Creston to Nelson, including Nelson yard. (2 miles and a jillion turnouts)
  2. Nelson to Tunnel #2, mostly covering Castlegar yard and the Celgar complex (2 miles, 1 in helix, 40 turnouts)
  3. Tunnel 2 to Grand Forks, mostly single track running but including Grand Forks yard. (3 miles, about 30 turnouts)
  4. Staging, both east and west
  5. Castlegar wye
  6. Cranbrook reverse loop
  7. Midway reverse loop

Note that the places most likely to have a short get the majority of a PSX unit – Castlegar yard and Nelson yard.

There are other wyes on the layout, but those reverse sections are simple – Since they’re the simplest wye with one turnout, I set them up to have the tail track reverse through a 3PDT toggle switch that also controls the turnout. The frog polarity doesn’t change!

Here are my two panels. The first includes the main portion of the layout, and breakers 1-3 and 5. It is located under Castlegar with the DCC system. This also includes 3 districts of 12V DC power for accessories, mostly servos. No protection in these circuits as of yet. Everything pictured is controlled from a switched plug and power bar.


The second is on the wall above the staging yard, and includes breakers 4, 6, and 7. The reversing wires are blue/green, as opposed to the red/black of the rest of the layout.


In addition to this, I added an SB3 booster. I’ve yet to overload my 5A command station, but plan to add more sound units to my roster and found a good deal on this older booster. The command station itself powers panel 1, and the booster powers panel 2. These helps keep wiring simple.

One thing I realized while isolating sections was that I had run my bus along the entire length of the railway, about 120′, although I thought I’d put in a cutoff! This led to unreasonably high voltage drop, signal degredation, loss of control of units in Grand Forks specifically, and slow reaction to fault current on part of the breaker.

One last improvement I made is that I was experiencing issues with my cabs plugged in, the displays showing odd characters on the screen. A quick chat with NCE cleared that right up. The total length allowed without additional power in the cab bus is 40 feet – not per leg, but total. To add power to the bus, there’s a 3.5mm mono jack on the rear side of the NCE UTP (throttle panel.) I simply added the power through my 12V DC buses that I installed to power servos. These used 3.5mm mono replacement jacks off eBay. I did this to the second last UTP on each run. Problem solved!


Now, my layout is operating near flawlessly. Wonder what the next issue will be to crop up?