I’ve just completed the only real “tricky” section of the lowest staging level of my new layout build, and have started testing the track. It’s not really tricky at all, just an area that won’t be the easiest to access once the next pieces of benchwork go in (it’s not completely obscured or anything, it’ll just have fairly low overhead space making it harder to work on later. Not ideal, but I lost 2 ft of width from my original planned layout space, and needs must and all that.) Schematically, the layout is effectively a very long dogbone, with all track between the ends laid out as a double mainline with crossovers as needed. Electrically, everything between the two balloon loops is wired linearly, as in “black to back, red to front” for both mainlines. This necessitates a reversing section on the mainline at each end, such that southbound trains on one mainline can be looped back to become northbound trains on the other mainline (and vice versa at the other end). This lowest level consists of the turnouts from the double mainline and the start of the staging yard throat, and of course the balloon track reversing loop. This is a DCC layout in N scale, with testing currently being done with a BLI F3 with Paragon 3 sound being run by an older Digitrax Zephyr (DCS51) because I inadvertantly left the Digitrax EVO (DCS210, not the 210+) destined for this layout in our storage unit last week. No circuit breakers, but eventually I’ll split the layout into power districts with a PM74, just haven’t gotten that far into the build yet to need more than 1 district.
Anyhow, had a slight issue with the AR-1 I picked up for the reversing loop. The relay would click, but the Zephyr circuit protection would trip and power cut to the layout. Per the AR-1’s instructions in such a situation, I attempted to dial down the trip current, and ended up taking it all the way to the minimum of 0.25 amps, but the Zephyr still tripped. Double checked wiring and ga
I am going to take this off topic for a couple of minutes but I had a low clearance yard and reverse loop on a previous layout. you can not put in enough atlas rerailers in the loops and after every turnout. Rerailing derailed cars can be a nightmare. Trust me on this.
I think the only way to do it is “real world” testing - just run each engine or combination of engines you plan on using through the reverse loop, and adjust the AR-1 up or down until they all go through OK.
I had trouble with one of my reverse loops where everything worked fine say going around clockwise, but the other way the reverser wouldn’t trip, or would keep tripping back and forth. Eventually found one of the wires connected to one rail of the reverse loop was also connected to a rail of the mainline. It wasn’t enough to trip the DCC system’s short circuit shutdown, or even to stop the engine, but threw off the AR-1.
I’ve also had a couple of sound equipped engines that balked going into a reverse loop no matter what. Adding a capacitor or one of the “keep alive” type devices to the engine seems to solve the problem.
You mentioned that you plan on subdividing your layout into power districts, but not immediately. Mine is divided, but only after a long time. I realized too late that I didn’t separate my track and bus structure to provide for power districts until it was too late. So, my separation was far from optimum. Given that you are building a second level on top of the lower one, it might be a good idea to divide things into power districts now before it gets to be impossible.
For my reverse loops, I went with solid-state devices immediately. They’ve always worked perfectly.
Oh, I know that frustration all too well. I’m upgrading to a little less than a 1-car garage sized layout from 8 years of stuffing too much stuff into a small apartment bedroom.
On this one, the low clearance is like 5" vertically on a shelf only 7" deep for about 3 ft, and one side is fully exposed and accessible right from the main aisle. The yard itself has about a foot of overhead clearance, and the reversing loop is primarily behind a backdrop within a very accessible helix. Only the start of the yard throat and the start/end of the reversing loop are in the lower clearance area. But there’s more than enough clearance to rerail anything that goes to ground, or clean track or other simple maintenance. Cutting in a new turnout or wholesale redoing the track work, that’s when the low clearance would be a real challenge.
Yes, I misspoke a bit there. When I said I’m not immediately putting in power districts, I meant just that I’m not that far into the build to where the first district division would even be yet. I’ve already planned where those division breaks will be and will gap the track and run busses accordingly when I get that far.
I’m seriously considering upgrading to solid state reversers right away. Minimize any issues down the line. The solid states, or at least the PSXX-AR I’ve mostly researched, seem a lot more customizable for trip current AND timing than the AR-1, which only allows a rather low-precision trip current adjustment. I may try a Frog Juicer as an immediate alternative to test, as I have them laying around, but that PSXX-AR has really caught my eye.
Thanks Greg, that makes sense. Set it for the maximum load from any and all expected trains in the section at a time (just 1 possible in my case) but less than the trip current of the booster.
To make sure I’m following the logic right, the trip current setting in the reverser basically sets a lower amp limit at which to flip the phase, right? So set it to the highest expected draw, and the reverser won’t see those amps drawn by trains as a short no matter how limited the draw is (for single-unit trains, say, versus the 4-unit jobs) until the train bridges the gap. Then the reverser senses the full amps from the booster (3 for the DCS51, 5 for the DCS210), trips before even reaching the full booster amperage, and flips the phase. Timing is everything though, as the reverser needs to be quicker than the booster. I think that about covers it?
Thanks for the help everyone. I guess this means I should be breaking out that sound ABBA set for my testing/dialing in of the reversing loop. Oh darn, shucks, what a bummer! Seriously though, I need to test performance on a grade anyway, so seems like a perfect time to unpack those and a string of cars, get this reversing section hammered out before some hardboard goes up and limits the easy access.
And I think I’ll pick myself up a solid state reverser too, see how that compares to the AR-1 myself. I’m pretty confident I want to go that route now anyway, save myself some potential headaches down the line. I have a (much smaller) side project where I could use those AR1s in a much less critical situation, so it’s no real loss spending some more on a couple solid states now for the “real” project.
A long time ago, I had a Digitrax AR1 on my layout powered by an NCE PH-Pro 5 amp booster. The AR1 worked just fine controlling a reversing section. But then I divided the layout into power districts, each controlled by a PSX circuit breaker. The AR1 remained on the layout inside one of the power districts. The circuit breaker constantly reset before the AR1 could react to a short. Finally, I had to replace the AR1 with a PSX-AR. The mechanical relay on the AR1 does not interact well with solid state components like circuit breakers.