What I am looking for, is a schematic for an automatic frog power routing module. Something like the DCC automatic reversing modules, but with only three wires. One to the frog, and one to each of the rails (that are insulated from the frog). The idea is that (assuming the frog is the "wrong" polarity) the module will detect the short, and then flip the frog feed. Basically an electronic equivalent of a SPDT switch mechanically connected to the turnout linkage.
Ideally, there is no connection (in any form, ie slide switches, reed switchs, haal effect ic) to the turnout control mechanism. It then has some application in two areas - trailing through spring loaded turnouts, and crossings. Particularly crossings, which have no moving parts, but still require polarity changing the acute frogs. Ideally the module would be totally solid state, and encased in epoxy.
And on a related note, does anyone have a circuit for a DCC reversing module?