I'm building an N scale layout on a 6'x3' table using Kato Unitrack and NCE DCC system. Can I use both "power routing" and "non power routing turnouts" together in the same layout? Or do they have to be just one or the other? I'm a novice in the hobby, any advice would be appreciated.
Unfortunately, the terms power routing and non-power routing cover most, but not all of the various turnout wiring schemes. Within each of the 2 categories are several sub-categories that may have many of the features and drawbacks of the other category. Sound confusing - it is. A good link for looking at various types of turnout wiring is at http://www.proto87.com/turnout-wiring-for-DCC.html.
You can definitely mix various types of turnouts on a layout. You just have to know which type you are installing, and wire accordingly. I believe some Kato turnouts have the capability to be switched from power routing to non-power routing.
Power routing turnouts have powered frogs, and cause only the selected path to have power (hence "power routing"). The non-selected path has both rails the same polarity, effectively shutting off power to that path. While power routing is very useful in DC, it is not particularly needed in DCC where every locomotive is individually controlled by talking to its decoder.
The power routing (and any powered frog) also prevents a locomotive from running a turnout set against it. As soon as a metal wheel hits the insulated rail joiner gap (or actual gap) between the frog rail and the extended frog rail of the track the train is on, there is a short circuit. In DC, the train stops and the throttle controlling the train is shut down. The rest of the layout that has a different throttle selected is unaffected. In DCC, the entire power district is shut down by the short, and if there is only one power district (common on smaller layouts), the entire layout is shut down. For a small layout, having the layout shut down over a short at a turnout being run the wrong way is often a good thing. On a larger layout, having the entire layout shut down by one operator's mistake is not a good thing, and is the primary reason behind mulitple power districts and sub-districts.
Of course, I'm not personally convinced that insulated (dead) frogs are the ultimate solution to a short circuit shutting down an entire DCC layout either. Sure, the train can now get past the frog of a turnout set against it without a short circuit. But the train will likely derail on the open points, and may still cause a short circuit with a derailment. I'd rather have the short circuit stop the train before derailing than have to rerail the train at a turnout. But that's me, and others will disagree.
The other drawback/feature of dead frogs (used by most non-power routing turnouts) is that short wheel base engines are subject to stalling on the dead frog, especially at slow switching speeds. And passenger car/caboose lights will flicker going over a dead frog unless they are specifically wired to pick from both rails on both trucks. But the dead frog does simplify turnout installation and wiring.
Note that some insulated frog turnouts (newer Atlas HO Custom Line comes to mind) have provisions for powering the frog if you so desire. The frog is totally insulated so the turnout never becomes power routing, but the frog has to be powered through a polarity contact on the turnout throw mechanism or switch machine.
Hope this makes sense
Fred W