I have a few Atlas N True-track turnouts with built-in switch machines. Last night I decided to try running them from track power. I touched the black and red to the live rails and got a quiet but audible buzz. Next I touched black and green to the live rails and heard the same. Didn’t get any movement either time. The DCC controller I was using was an MRC Prodigy Advance². It’s only outputs are to the main track and to a program track. So what should I be using as a power supply for these turnouts? The turnout package just mentioned connecting it to “Accessory Power” which on my MRC power packs in the past had a separate pair of screws that supplied AC for such things. Before trying last night’s experiment I read articles from people who sometimes used track power and other times used a separate booster for turnout control. Anyone know of any Atlas documentation on how to power these turnouts? What do you use? Any decent power supplies available at Radio Shack? For stall-motor switch machines I’ve read about people using everything from “wall wart” transformers to car battery chargers. Finally, what’s a good accessory decoder for the Atlas turnouts? Does it get it’s power from the track power or is it supplemented by a separate power source that is then simply switched by the DCC decoder?
I found the answer elsewhere… These are DC powered not AC, so I’d need a capacitor if I wanted to power them with track power and the included momentary SPDT switch. I saw the NCE Snap-it stationary decoder. Looks nice but anyone know if it has enough oomph to control a pair of turnouts simultaneously (as in a crossover configuration for crossover routing)?
So do you have a burning desire to power / control them from the DCC system. Most people put in a second (much cheaper) power supply for accessories like turnout motors and keep the expensive DCC power for the trains.
Unfortunately, I do not use DCC for my turnouts so I am unable to answer your question concering the potential power output of a Snap-it. I would guess not since the product description in the catalog specifically says, “Control one twin coil switch machine”.
We’re all going to say the same thing - don’t run your turnouts off of your DCC system. You can control them with DCC, but that’s a different matter and the power must come from elsewhere.
I run my turnouts the way I always have, off the accessory terminals of an old DC power pack. It’s the same way I did it 50 years ago, when that was a new DC power pack. However, I did add a Capacitive Discharge circuit to give me a better kick for flipping more “stubborn” mechanisms like Pecos. Each turnout is wired to a single-pole, double-throw (SPDT) momentary-contact toggle.
If you prefer, you can get stationary decoders to run your turnouts, but you don’t have to do that with DCC.
I am surprised you even tried to operate a twin coil machine via DCC. No way. Not even with a cap. You need a lot of education on what you are doing
Use a Snapper powered by an AC from a transformer or the Accessory terminals of an old power pack which is usually AC. Even the DC terminals of an old power pack will feed a Snapper but turn the power pack all the way up if it is not used for anything else.
A Snapper will power more than two turnouts.
Rich
I wonder how people run NCE Snap-it stationary decoders from external power sources: http://ncedcc.com/images/stories/manuals/snap_it.pdf The manual mentions the + and G terminals as inputs for supplemental external power - but would an inactive DCC system due to a tripped breaker still allow the Snap-it to flip the turnout via the push-button interface? I supposed it’s not a huge issue in this case since all of the turnouts have a manual throw built-in. I’d like to control these turnouts with DCC because I have a webcam set up and a USB interface to my DCC system from my computer. Being able to align turnouts via the computer would allow me to control the trains remotely from anywhere.
I wonder if that’s why I was looking for further documentation on this from Atlas. 
Well other than being a large waste of realtively expensive DCC power, there’s no real reason why a twon coil switch machine wouldn;t actually work on DCC power. At leas,t the Atlas and other twin coil types - the Kato ones ARE DC only and rely on the polarity revering to throw back and forth. A twin coil type will work on AC or DC, you just have to make sure to connect the proper wires, and ONLY MOMENTARILY.
Still, this is NOT somethign you’d actually want to do other than maybe to test a switch machine. There are several options for stationary decoders if you really want to control the turnouts from your DCC throttle, but this is fairly cumbersome in any brand of DCC system. Your absolute cheapest option would be to pick up a power pack like an MRC 1300 and (optional but highly recommended) a Circuitron Snapper, and run the turnouts from that.
–Randy
Looks like that other source was wrong… they are indeed AC - here are the instructions from the packaging: http://sdrv.ms/UALfiU
Just a brief technical note - you would need a diode bridge to rectify the any AC signal (or DCC, which isn’t quite the same ) before feeding a capacitor.
I’ll say it again, twin coil swicth motors are AC OR DC they work fine on either. There is less contact arcing with AC though on the momentary contacts.
A capacitor discharge powers suppyl liek the Snapper is more than just a capacitor. Not sure about the Snapper, but the one I built for myself way back when took an AC input, it had a diode. This is part of what made it so ‘snappy’ - a cap charging from rectified AC charges to the AC peak not the RMS voltage, which is the higher of the two. Output from the CD power suppyl is DC, to the buttons and then to the switch motors.
So, prior to installing a CD supply, the turnouts were controlled by AC fromt he accessory posts on the power pack. With the CD machine, the turnouts were seeing DC fromt he output of the CD supply. The large resistor in the CD supply limits current if you hold the button down too long, or if it gets stuck, preventing the coils from burning out.
–Randy
While twin coil switch machines are AC or DC, there is a reason they will not work on DCC power. When powered by AC, the impedance of the coil increases with frequency, and at the frequencies of the DCC signal, the impedance is enough to prevent the coil from operating.