Advice with Reversing and Switch Control on a Traditional Layout.

That will be a fun layout.

Powering turnouts (Track Switches) with fixed voltage allows you to operate turnouts while trains are not powered on the track.  (Turnouts with fixed voltage will not care if track power is on or off.)  Turnouts are best wired for non-derailing.

"Will that plan work for the North and South Sidings?"  Yes, with ins pins at both ends.

"or is there a challenge presented with the derailing feature and/or reversing loops?"  Not with aux powered turnouts.

I "second the motion" of Susan D.;  i.e., provide fixed 14v to all switches so they are wired separately from track power. The biggest benefit -- locos on the rails could be run via the KW's throttle settings, and that would not affect the "snap" of switches.  Your KW has a fixed 14v post.  Many hobbyists use that source for power to switches, lighted buildings, and action accessories through a distribution terminal.    Since the switches and action accessories only draw power when activated, the KW can handle the loads. Go for it!

Mike Mottler    LCCA 12394

Great looking track plan!  I am also a sucker for dealer display postwar style layouts.

You should be fine with SPST switches to control track power to the sidings.  The power for the switch machine comes from the center rails of the switch, with all three legs of the switch being electrically connected, so you should still have power to the switch mechanism from the other legs of the switch even if you isolate one or two legs of the switch. 

There are two variations of the 1122 switch that you can read more about here: http://pictures.olsenstoy.com/searchcd2h.htm  It is my understanding that the control rails are different between the two variations, among other things.  The diagrams will also help you when you decide to alter for constant voltage.  I think there have been a few topics on that issue on this forum.

I also agree that you will have more reliable switch operation with the constant voltage.  Not a necessity, but it will be a very big improvement.

This is exactly the advice I was looking for, thanks! 

As for fixed power, I also have a ZW and plan to use it for variable and fixed power. 

"You should be fine with SPST switches to control track power to the sidings.  The power for the switch machine comes from the center rails of the switch, with all three legs of the switch being electrically connected, so you should still have power to the switch mechanism from the other legs of the switch even if you isolate one or two legs of the switch." 

Yep.... If you don't want to mod those 0-27 turnouts leave them alone and just use iso pins; next to the anti derail pin, or further into the siding if you want. 

It's a "block wiring", but slightly different than what you may usually read as being a block. 

You may want to divide a block siding into two blocks. Then you can park a loco but keep passenger cars, or operating items powered while an engine is "cooling". (by need or just "chillin") 

The car portion can have constant power if you want or be switched between variable and constant. (Just dont let the loco onto a constant voltage )    You can operate a parked whistle or bell tender while running something without one too. I do this. My fav. is a railsounds tender. I like the soothing parked cycling rhythm as background noise.  I also turn a bell on and leave it as I used to hear them for hours nonstop at a few places I frequented.(I don't run engine sounds much or loud if I do.)

You can also use a separate transformer but you need to phase it to the other for safety and from double voltage, etc. (something I could do by second grade with instructions over the phone)

Zw ...all set

You want 15a switches for a zw.

or 10a fused.

I looked at the track closer. The left S turn may pose an issue for backing, and on just a few oddball trainsets and odd couplers you'll get a coupler that slips out or binds and the trailing car/B unit gets dragged of the rails. Partially because it is 0-27. The S is more of a worry in other scales than O because we have deeper wheel flanges. The common fix is a short piece of straight in the S

I wouldn't pull it out. Maybe move the station....maybe not. It looks great as is.

Between the closely spaced turnouts you may have dead spots añd power issues. Going slow some trains may have issues. 

I suggest a center rail feed between every turnout. Especially those real close ones with shorty pieces. Don't pass the power thru one. Jump around it because wire does that much better of a job with amps than rail tab connections, etc that hold them together. 

Liomel suggestedt since prewar. one lock-on center feed at every turnout exit (block is a different feed)  The outer rails do a better job because there is simply more metal and connection tabs total. Seldom need to worry there. If you find hollow pins (seam) Replace the center pin with a solid one. Those can rust from the inside out. The center one can red hot . Again, the outer can handle more ,but any sign of rust and I pull at least one of those two for a solid pin.