One thing I learned from designing computers is that there is always a simple elegant solution to any problem - you just have to search for it. In this case that turned out to be a "Hex Frog Juicer". All I had to do is isolate the center section and power the frogs of the 4 switches from the 1st 4 outputs of the juicer and power the left and right legs of the crossover section from the remaining 2 juicer outputs (with the jumper set to force both to flip polarity together). Input is from the DCC power of the main (outside) track. Nice and simple, no programming, no muss, no fuss, and it worked like a charm first time.
One minor complication is that I have a passing track on the outer / main loop (on the longer right side) so I got a dual frog juicer to power those 2 frogs (input power to the juicer from the main loop DCC power). I also have 2 single sidings on the center crossover section - in that case same solution, a second dual frog juicer powers those 2 frogs with the input power to that coming from the crossover DCC power.
For now I'm flipping the switches manually to check everything for proper operation, but so far everything works fine. I'm working on wiring the switches now (PL11 top-mounted solenoid type). Power will be a separate 16VAC 40VA power supply to a CDU with push button switches to flip either pair of switches: the UL/LR pair to reverse a CW train and the UR/LL pair to reverse a CCW train. I've designated the "short side" (left side) switches UL and LL as "entry" switches and the right side switches UR and LR as "exit" switches. To reverse a CW train, I'll just wait till the back of the train clears the LR switch then flip the switches. To reverse a CCW train, I'll wait till the back of the train clears the UR switch then flip the switches. I won't need to do anything more as a single train detector (TD in the diagram, located at the farthest point of the "long side") will flip the switches back to the main in both cases. I'll only be running one train at a time and the max length of that train in my layout is 12 ft (bottom straight + left loop or top straight + left loop). So the train detector just needs to be at least 12 ft from the right side switches to make sure the train is clear of the crossover before the switches automatically flip back to the main.
I've attached a picture taken from a ladder - this "upper layout" is suspended from the ceiling at about eye level. The lower layout hasn't been started yet. After the upper layout wiring and the backdrop are complete, I'll be adding 3" wide clear acrylic strips on either side of the subroadbed (which is 1/2" plywood glued to 1/4" foamboard), to keep the trains from falling on the floor in the event of a derailment. Everything is top mounted (track, wire and switches) because there is LED strip lighting under to light the lower layout.
"Big Daddy" Dean (nickname from my 3yo grandson :-) )
Intriguing.
Would the idea be to run two trains in opposite directions on the outside oval, using the figure 8 to avoid head on collisions?
Rich
Alton Junction
I can see simple ways to do this but it can get complicated by running more than one train.
See the link below, about 2/3 way down the page (reversing subjects) the paragraph "using double crossovers with balloon tracks". Not certain(!) but that might be your answer; e.g. a preferred way to handle would be to put a auto reverser on each (right and left) end of the loop, with the middle non-reversing.
http://wiringfordcc.com/track_2.htm#a43
BTW, Tonys Trains can be most helpful on the phone. I used their advice to settle on inexpensive OG-ARs on my two reverse loops (each a sub-district from my single NCE booster) and a OG-CB as a 3rd sub-district. I've been happy with those components.
https://tonystrains.com/shop/?s=og
Paul
Modeling HO with a transition era UP bent
I have seen many good explanations of how to wire a reverse loop for DCC and also how to wire a double reverse loop (dogbone with a reversing loop at each end). However, I haven't been able to find a good explanation of how to wire a "Figure 8 Double Reverse Loop", which electrically is basically an oval overlayed with a Figure 8 (crossover in the center and 4 turnouts where they overlap).
Like a lot of things, it seemed like a good idea at the time - it provides a way to reverse the direction of a train running either CW or CCW around the outer loop, but the wiring for it has turned out to be a bit complicated to figure out.
I know I need to isolate the center crossover section from the main outer loop, and add a reverser circuit to control the polarity of both sections, but I'd like to have trains running continuously if possible by just pushing one button to flip the upper left / lower right turnout pair for trains running CW (or the upper right / lower left pair for trains running CCW) and have the turnouts switch back to the outer loop when the train exits the crossover section.
I was originally going to wire this part of my layout with DC and got one suggestion for that involving some latching relays and 8 train detectors, then someone suggested I use DCC instead (because "it would be a lot easier to implement") but I haven't been able to find a circuit for that. FYI, I'm using PECO Electrofrog turnouts and will only be running trains that will fit in the shortest section of the "X" crossover (just over 5 ft). I could also simplify things a bit to reduce the possible combinations by only having trains enter the crossover section from upper left or upper right with the lower turnouts being "exit only".
Any help or suggestions would be appreciated. Thanks.