I want to isolate some existing sidings so as to park engines with the power off. the layout is DCC and there are at least two feeders on each siding. I want to control the siding power from a central panel. My question is can I run the feeders from one side of the track to the panel toggle and back or is it better to run both sides to the panel and back?
Are you asking if you need to isolate both rails from power or if you can isolate only 1? On my outside third rail O scale switching layout, I isolate only the outside rail which is the positive polarity rail. Both main rails are negative and are not isolated. Although I have 3 rails, the concept is the same as if you were to only isolate 1 rail rather than both. You can take either approach. Some may tell you to isolate them both. Others may tell you only doing 1 is fine.
Since you specified DCC and wanting to control everything from one central point, I would recommend isolating a single rail (which is all it takes) and inserting a normally-off SPST relay in that rail's feeder. Inexpensive 12vdc relays can be had from any on-line electronics supplier.
Then you can have a power-control schematic at your central point, with a SPST toggle for each relay set right in the track diagram. Power the whole works with a toy train power pack or a 12 volt DC wall wart. Since relays don't draw much power, #24 communications wire is adequate for the interconnectors.
I use a similar arrangement with SPDT relay contacts to control live-frog polarity in a spring switch.
Chuck (Modeling Central Japan in September, 1964)
I isolate one rail of any "killable" siding, and run a feeder wire back to the control panel. I have a connection from my track bus to the panel, too, and use a single-pole, single-throw (SPST) toggle to connect them. The other rail gets wired directly to the other side of the track bus.
My wire runs are short, so I use #22 feeder wire between the toggle and the rail. Since only one engine (typically) will be on this short siding, I'm not worried about power capacity or resistive loss for that short run. Chuck's relay solution is more appropriate if your panel is a long way from the siding, because you don't have to worry about power loss to the track over the longer lines.
It takes an iron man to play with a toy iron horse.
I have used Caboose Industries ground throws with built-in SPDT contacts
Works out pretty cool
Ken
Why would you need to shut off the power to the track with DCC? I am in the process of wiring my layout and didn't plan on a control panel since I went with DCC.
cgrubb80Why would you need to shut off the power to the track with DCC?
You're right, of course, in that you don't have to shut off the tracks and kill power to the engines. But, there are reasons to do it in some cases.
I have a couple of trains of lighted passenger cars. They draw power all the time, and I have no way of shutting them off. So, I have sidings with power kill switches so that I can park them and turn the lights out. This saves bulb life in the cars, and, probably more important, reduces the power load required on the DCC system. The same goes for lighted cabeese. Even if all you've got is tiny LED marker lights which use hardly any power, you want to shut them off for "realism" when they're not in use.
Standard non-sound engines don't use significant power when idling. However, sound engines do use power when idling, and once again will go against those precious amps your DCC system can put out. Some sound decoders have shutdown sequences which can silence the engines, but others do not. I prefer to have my "out of service" engines cold and quiet.
Finally, think safety. Sooner or later, you will key in the wrong engine number, and stand there with a puzzled expression when your train won't move. Then, the engine that you did call up will run a turnout and derail at the other end of the layout. If that engine is on a dead siding, it won't budge.
Toggles and wires are cheap. I have a couple of isolated sidings that I never shut off. Others I keep off most of the time.
MisterBeasley Standard non-sound engines don't use significant power when idling. However, sound engines do use power when idling, and once again will go against those precious amps your DCC system can put out. Some sound decoders have shutdown sequences which can silence the engines, but others do not. I prefer to have my "out of service" engines cold and quiet.
Slightly OT - a prototype 'sound effect' that I'd like to see somebody model:
JNR C58 class 2-6-2 sitting still, waiting for its assigned train to arrive behind a catenary motor - just a gentle hiss, and a few wisps of smoke from the stack. Everything else in the area was quiet, too.
Then the safeties lifted! A huge plume of steam shot skyward, accompanied by a roar like Niagara Falls in full flow.
Imagine the reaction of some mundane visitor to your layout space if you could stage that with the push of a button or the flip of a toggle. (I might arrange it, but with a fixed speaker, not on-board sound.)
Finally, think safety. Sooner or later, you will key in the wrong engine number, and stand there with a puzzled expression when your train won't move. Then, the engine that you did call up will run a turnout and derail at the other end of the layout. If that engine is on a dead siding, it won't budge. Toggles and wires are cheap. I have a couple of isolated sidings that I never shut off. Others I keep off most of the time.
My original suggestion to use ralays was driven by the realities of my double-garage filler, where the power for those spring switch relays has to run along sixty feet of aisle-side fascia to reach the farthest one from the CTC panel. That's a mighty long haul for a DCC track drop. Doing it with three wires would be an even longer haul for my analog DC control system.
Chuck (Modeling Central Japan in September, 1964 - analog DC, MZL)
I have a small layout that goes around my family room about a foot and a half down from the ceiling, only place the wife will let me have it. I put in a storage track to keep some of my engines and use a Atlas connector to cut the power to it.