Dead frog

If you could get by with a dead frog, insulated, no switching would be required. 

You could have a signal and smash board protecting the gantlet track, and switch the polarity based on who has the signal/board lined for their movement.  The train drives up to the signal, the fireman/head brakeman gets down and lines the signal for their use, the signal clears for the route, then the train crosses.  Or have the dispatcher control it.

One juicer

Assuming that the On3 track enters and leaves the gauntlet from the same side, then I don't see why you'd need two frog juicers.  Both frogs will always need to be at the same polarity, so one juicer ought to do the trick.  That's certainly how I'd do it, assuming DCC track power.

"switch the polarity based on who has the signal/board"

Sounds like a good job for a tortoise or Blue point controller. Throwing the controller sets the signal or smashboard or whatever route protection there is and also powers the frog? Probably the hardest part would be creating a scenario where a standard gauge line would want a 30 inch line crossing on it's bridge, they usually tried to get narrow gauge traffic into standard gauge cars ASAP instead of helping them compete? .DaveB 

Dave B................

...............Both lines are owned by the Adirondack Southern Railway and it's subsidiary, the Abanakee Lumber Co. The standard gauge interchanges with the D & H while the narrow gauge roams throughout the southern Adirondack Mountains in upstate NY.

Peter

Gauntlet Track

Peter,

I can't speak to Dual Scale Gauntlet, but I can tell you about the 26' HO Gauntlet track that I put in around my helix. Here is a link to my layout build referencing my Guantlet track.( http://www.railroad-line.com/forum/topic.asp?TOPIC_ID=37755&whichpage=3)

I used two Fastrack HO turnouts, one #6 curved and a #5 straight. By cutting them just behind the tapered part of the point rail for the entrance an exit points of the Gauntlet. As you can see in the first photo, I started to make the main part of the track and very quickly realized it was going to take forever to complete, so what I did, was to use Flex Track. Buy removing every thirteenth tie and replace it with a PC/Copper tie in order to fasten the extra rails. I your case you would only have to add one rail for a total of three. I also used a single frogger to cover the frogs on both tracks.

If you add the On30 rail to the outside of the curve. Maybe you can find someone on eBay that makes Fastrack turnouts in the dual scale, plus you can visit Fastracks they have downloadable pdf templates of turnouts, etc.