Might seem like a silly question but can I just double gap a siding on my layout and wire switches into the feeds to switch between layout track and programming track? Every schematic I've seen so far seems to show a separate track unconnected to the layout?
Yes, you can do that. I think you will need to switch the layout off rather than the programming track on. Which system are you using?
Yes, you can do that, and it can be an easy and elegant solution...provided you keep the axles that can complete the circuit between the rails within the gaps. If you let one wipered axle cross over and bridge the gaps, and you are programming an address in Paged Mode, you will convert all addresses in decoders throughout the same power distribution district...including the whole layout. So, as the gentleman has said, above, you would be better to ensure the rest of the layout is the part that gets switched off when you use such an arrangement. That way, no "D'Ohhh!s" Trust me, it'll happen...several times, and at least once too many. What I did was to use my turntable lead, which happens to be front and centre on my yard module. It is gapped naturally at the pit, and also at the end of the diverging route of the turnout that grants access to the lead. I place/drive an engine between the ends, and I flick the toggle on an DPST below the layout that kills power to the rest of the 'world'. Then I can programme. Here's how it works: your main bus off the DCC base station goes to either of the two pairs of posts on an DPST. The other pair feeds the rest of the layout, but not the turntable lead. So far, we have a DPST between the rest of the main bus to the layout and the power supply/base station. The lead still has no feed. This is the cool part: on the same posts to which the base station output comes, you share those by wrapping the power-side feeder ends of the TT's lead track around them. So, just to be crystal clear, both the base station's output wires and the one end of the lead's feeders are wrapped around the same two posts and screwed down. The other ends of the feeders simply get soldered to the gapped lead as you would any pair of feeders. Thrown one way, the entire track system, including the TT lead, gets normal power. With the toggle thrown the other way, everything else is unprogrammable becacuse it is dead, and only the TT lead is powered for your convenience. I hope that helps.
The safest way to do this is to have a section of track that can be turned off completely between the programming section and the main line. This avoids the chance of reprogramming everything on the main but more importantly it will avoid the chance of frying the programming outputs on your command station. If a loco or metal wheel is bridgeng the gap between a powered track and the program track, full track power is fed back to the programing outputs. Most systems won't survive that. Martin Myers
Hi Andy, Thanks for asking the question because I was thinking of doing exactly what you proposed. After reading the responses I see the potential problems. Brian
How you wire your program track depends on which type of program track your system has. Crandell's response is for a system that does not have a separate program track output(i.e. Digitrax Empire Builder, NCE Power Cab) and Martin's response is for a system that does have a separate program track output(i.e. Digitrax Zephyr, Digitrax Super Chief, NCE Power Pro). Without separate programming track outputs, as Crandell said, you just need a switch to disconnect the rest of the layout when programming(one correction though, he was describing using a DPST switch, not a SPDT). Another option is to use NCE's Auto-SW, which will shut off the rest of the layout automatically when it sees service mode programming commands. If you have separate program track outputs, like Martin said, it is best to have a section of track that is dead between the program track and the main when the program track is set to program so that you can not short the main outputs to the program outputs on your command station. The easiest way to do this is with a 4PDT switch that switches the program track from main to program and at the same time switches off the section of track between the program track and the rest of the layout. Here is a good description of how to do this.
I have done exactly what what you are talking about on my layout using Digitrax. I have a rotary two deck switch with three positions. I have a stub siding that has a loco length section at its enterance that is electrically isolated (double gapped at both ends) and the rest of the siding. When the switch is in position 1, both sections are wired to DCC. In position 2, the short section is dead and the rest of the siding is connected to the programming leads from the DCS100. In position 3, the short section is again dead, and the long section is now powered from the dcc bus through a decoder. This gives me an effective DC section to check new locos. This all works better then I had hoped and was not hard to wire with the rotary switch.
Hi Sean, I think you have an excellent solution, but I don't understand the #3 position. What kind of decoder do you use here and what does it do for you?
That's a GREAT idea Sean! I use the 4PDT method to create a dead spot between the programming track (actually the lead to the turntable) and the rest of the layout.
This is an N-scale 1 amp mobile wired decoder. The decoder allows me to run a DC engine, no decoder installed, to test it out before installing a decoder. I could have made the switch turn the second rail section to a DC throttle, but I had a spare decoder... so the way it works is the decoder has the pickup leads hook directly to the DCC bus and the motor leads hooked through the 3 position switch to the rail. Instant DC. No need for a second power pack. I left it set as loco 03 and it works great. There is a possibility of shorting out the decoder I suppose, but it was a cheap $12 one so it was worth a try and it works fine. Hasn't shorted out yet.
