My daughter and I are in the process of building our first N scale railroad. Though we have been making decent progress, we have hit a stumbling block that I can’t seem to sort out. Our layout has several reverse loops, some inside of another. We have purchased two PSX-AR’s. We are using a NCE Power Cab to control the layout. I have run 18 gauge speaker wire from the power cab to serveral grounding bars (the grounding bars are what you would find in your house hold fuse panel), and from those I have 20 gauge soild bell wire running to the tracks. I have been soldering feeders to all sections of flex track and there are no sections over two feet without a feeder to them. All the switches are Peco insul frogs and have plastic insulators on the frog ends of the turn outs. At this point we have no switch machines, so we are just flipping them manually. Right now we only have two engines, an Atlas that came with a decoder installed, I think Lenz but not positive. Also a Bachman cheapy that I put a Digitrax decoder in from Tony’s Train shop. We are having trouble getting consitent operation through the loops. Most of the time the engines will make it through but other times it will shut down the Power cab. The Atlas seems to be the most reliable while the Bachman seems the most troublesome.
I noticed tonight that the Bachman was shorting out on the switch, less than one inch from the gaps that insulate the reverse section. I looked at the engine while it was on the shorted out spot and can’t see any reason for it to be causing a short. Is it possible that one engine is drawing more current than the Atlas and causing the short? The Atlas will run through this spot at high speed and low crawling speeds with so much as a hicup.
I have programmed the PSX-AR’s per the instructions. I moved the program jumper to pins 2 and 3 then set the CV49 in the power cab to 01.I then jumped J6 1 and 2 on both units.<
By “rambling,” as you called it, you’ve revealed a likely problem. The Peco insulfrog turnouts have a narrow plastic section where the rails of different polarities come together. It’s so narrow that engines with wider wheels, which cheaper engines sometimes have, will sometimes short when crossing the frog because they bridge the gap of the plastic insulator and touch both rails at once.
And therein lies the solution. Ask her for some clear nail polish, and paint it over that narrow insulator to coat the rails, just for that half-inch or so where the wheel might bridge them.
Ahhh, Mister Beasley, you are putting your fine reputation on the line with that do or die advice - - - LOL.
You may be right, you may be wrong.
There are a lot of things that could be going wrong here, and a track diagram would sure help.
More than one reverse loop, reverse loop within a reverse loop, two auto-reverser units in play, NCE Power Cab as the power source, wiring issues, gapping issues, sometimes it all works, sometimes it doesn’t all work.
It will be pretty interesting to see how this all eventually sorts out.
The first thing that comes to my mind is that the reverse loop within a reverse loop could be causing you problems. To get that to work correctly, you need some special wiring, I think. I will try and explain as best I can.
The “first reverse loop”, or the outer one, can be wired up normally. That is, the input to the auto reverser would go to the main power bus, and the output would go to the “loop track bus”. Now here is where it might get confusing. The input to the reverser for the inside loop should connect to the output of the outer reverser, or the “loop track bus” above. Then the output of the inner loop reverser would go to the inner loop track.
The thinking behind this is that the outer loop (first reverse loop) can change polarity, so the input of the reverser for the second loop (inner loop) must match that polarity so the polarity change of the inner loop can match the polarity of the “first reverse loop”. In theory, this makes sense. But to perfectly honest, I haven’t ever tried this. Also, the trip point of the “first revers loop” reverser may have to be higher than the trip point of the reverser used for the inner loop. For a 5 amp system, this would work. But for a Power Cab with a lower current output, you may have a problem setting two different current levels that would work within the parameters of the Power Cab’s current ratting.
Anyway, it is something to consider.
Another thing; The reason that we use heavier wire for the main bus is to reduce the resistance of that bus. Track feeders should be kept short, around one foot or less. That is not because they can’t handle the current. Again, it is to keep the resistance down. These two factors also play a part with the auto reversers because they are current devices. If the wire to them is small, they may not
Try Mister Beasley’s fix. I’m also an N scaler and painting those Peco frogs has solved more then one shorting switch. Remember that the clear does wear off and the short will return.
Also check he gauge on the wheels. Out of gauge wheels will add just enough slop at the guard rails to allow contact with the other rail through the frog. Peco switches also have a fairly wide gap between the guard rails and the rail. That was fine before DCC. DCC has much faster acting circuit breakers then most DC power supplies. DCC sees that momentary short and shuts the power off.
There is a lot going on here and a lot that we still don’t know about.
A lot could depend on where you placed the gaps and how you wired the two rails throughout the layout.
So where did you gap the rails?
And, how are the various feeders connected to the bus wires? In other words, how are the outer rail and the inner rail powered through the layout. It is all a matter of keeping the wiring in phase on the main (non-reversing) section of the layout.
Not that it matters to the issue at hand, but where is that elevated track leading to, and where will it eventually connect to the rest of the layout?
You mentioned that the two PSX-AR units are in place, but there are no switch machines in place and that you are moving the point rails manually. Have you left the springs in place on the Peco Insulfrog turnouts?
Which sections of track are you treating as reversing sections with those two PSX-AR units?
Tell us more about the two locos and their decoders. Which Atlas loco is it? Which Bachmann loco do you have and which decoder did you install?
Another vote for MrB’s fix. The bachman is shorting out on the switch before is gets to the gaps that start the reversing section. At times both engines make it through so the reversing section works if you get past the switch. It is an easy fix and will tell you right away if the problem has been corrected. If the problem persists then a much more detailed investigation is required.
Mr. Beasley hit the nail on the head. The Bachman has wheels that are 0.015" wider than the atlas that runs whith out issues across the same switches. The nail polish confirmed what the issue is. Being both of these switches are located inside the tunnel, what do you recommend as a permanent solution? Would cutting the rails with a Dremel work? To me it looks like if I cut gaps across both rails that it would work. Thanks for the help thus far. I’m sure I’ll have more questions later.
I don’t believe I’d be trying to cut the rails with a Dremel. Of course, that’s just me. The nail polish trick is an old one, but should last a good while before a touch up is needed. Now you see one reason turnouts in tunnels is usually best avoided. I’m not saying “don’t do it”, it’s more along the lines of “make an informed decision if this is what you plan to do”.
Replace with electrofrog and power frog either from switch machine contacts or with something like the Tam Valley Frog Juicer. Then it won;t matter if the wider wheel spans the two rails where they come together at the frog. Just before to gap the frog rails beyong the frog as well.
