It recently came to my attention that some folks are not having good results using the DCC Specialties PSX-AR Auto-Reverse/Circuit Breaker. I found that after reading the instructions (more than once) that the PSX-AR has a rich feature-set, including the ability to simultaneously control a tortoise. If not for that ability I would have used Tam Valley Depot Dual Frog Juicers as they are less expensive and I have had good luck with them in the past. There are several instructions in the PSX-AR manual that may not seem important, but, are necessary to follow in order to perform all functions correctly.
The goal was to have a reversing loop at each end of about 70 feet of end-to-end track so that a train could run continuously on the lower level while working on expanding and completing the layout (running up to the upper deck). This meant that I needed a means to automatically change the turnouts leading into the reverse loops. During operating sessions I plan to dis-engage the reversing loops to force prototypical A – B running and utilize parts of each reverse loop as staging. Later there will be a third reversing loop just outside of upper-level staging.
Below, in no particular order are a few things I found to achieve my goal for the lower level:
01. Offset insulating joiners. Before doing this I found that a locomotive would stall briefly before continuing after crossing the insulated gap. The reason appears to be that as both front wheels crossed the gap at the same time it introduced a “hard short” at the same time as the reverser was triggering the reversal of current. The turnout that was controlled by the PSX-AR would close or throw as it should, but, the approximately 2-second delay while the circuit breaker reset was annoying. As soon as I re-worked the insulated gap to allow an offset of between 1/16″ and 1/8″ (recommended by the documentation), the hesitation stopped. Below are photos (1 & 2) of N-Scale track before and after re-working gap.
Gaps side-by-side – WRONG! Gaps offset 1/8″ – CORRECT
02. Power PSX-AR directly from booster. There are 12 DCC Specialties circuit breakers near the reversing loop at the west end of the layout powered in two banks by two boosters. It was very convenient to run a wire from the right-side of the input side of the last breaker ** in bank 1 (Breaker 5) to feed the PSX-AR. (See photo 3 below.) Great! Worked well right off the bat. However, the PSX-AR at the other end of the layout was located on the other side of the aisle from another bank of 5 breakers. Running a wire from the input side of the last breaker would involve fishing the wire up one wall, across the ceiling and then fishing it down to below the benchwork across the aisle.
This was too much effort, so instead, I connected the input of the PSX-AR reverser to the nearby track bus. BIG MISTAKE! No matter how I changed the wires to my controlled turnout, changed the output to the reverse section of track or just stood there tearing out my hair, it would not work. The next step was to swap out the first PSX-AR for the second since the first was working quite well. Fortunately before going to the effort a re-read of the instructions determined that I was at fault, not the reverser.
The next step was to run a temporary pair of wires from the input side of the breakers, across the aisle, under the floor mat, and hook them up in place of the wires from the track bus. Voila! Trains can run for hours without intervention. The temporary wire is still there so the effort of running a permanent wiring solution remains to be done. At least I can watch and hear a locomotive running while performing that task.
** DCC Specialties PSX-series circuit breakers are daily chained together on the input side (e.g. A pair of wires from the booster is connected to terminals 1 & 2. Then short pair of wires (just about 4″ long if breakers are co-located) connects from terminals 3 & 4 of the first breaker are connected to terminals 1 & 2 of the next breaker and so on. The last breaker in the chain remains with no wires coming out of terminals 3 & 4.
03. Not as critical is setting up the PSX-AR to initiate with the controlled turnout set to the main (or which of the two possible choices you wish) upon power-up. Out of the box the PSX-AR will set the tortoise-controlled (or other switch machine) turnout to the same direction when the power is turned on. Therefore, you have a 50/50 chance that you need do nothing. If you find that the default is not your preference, merely reverse the two wires (22 ga. blue/gray pair-see photo 4 below) leading to your tortoise (or other device) at the PSX-AR terminal block. The 4-position green terminal block on the bottom left of the PSX-AR was soldered there to make it easier to wire in a remote status LED in the future. It turned out that it was a boon when it became necessary to reverse the blue and gray outputs to the tortoise so that the turnout would initiate with the points set to the main-line route.
04. As with any reverse section of track, the section controlled by the reverser must be longer than the longest train unless cars use plastic wheels and are not lit. If your rolling stock has metal wheels or you have track-powered passenger car/caboose lights or use pusher locomotives, you can have a problem when the lead locomotive leaves the reversed section and trailing rolling stock is yet to enter. Each wheel that crosses the gap at either end causes the reverser to try to match polarity with the adjacent track section outside of the reversed section.
There may be other solutions to the problems encountered with this installation, but, this worked without the next step of setting CV’s. Eventually the breakers, including the reverser/breakers, will be set to take advantage of other features and to set trip-amperage thresholds to match the various power sub-districts.
After running trains on layouts with few or no breakers and encountering myriad short-circuits that also stopped trains far from the short, I decided to break my layout into much smaller power sub-districts. The layout, when complete will be considered medium-sized, but when it is complete there will be at least 17 sub-districts protected by PSX-series breakers and at least 3 protected by reverser/breakers. The hope is that any short circuit will only affect the train that is causing the short.
Please leave a comment if you have additional insights into use of these breaker/reversers or if you have any questions.
Model Train Operations 