I'm building an outdoor G Gauge layout that is two reverse loops connected by a single track main line. I am using the "spring switch" feature of the LGB turnouts to always route the train clockwise around both reverse loops. I am using the LGB #1015K Reverse Loop Set on each loop - this is essentially a bridge rectifier with the single track main line on the "AC side" and the reverse loop on the "DC side", so the polarity on the reverse loop is always correct for the clockwise operation. This leaves me needing to manually reverse the polarity of the main line each time the train get into each reverse loop.
I understand changing from DC to DCC would solve this problem, but I don't want to make that investment. I understand that there are automatic reverse loop controllers that would automate this. However, most seem to depend on either optical or magnetic sensing of the train to initiate the polarity change, and I would prefer to avoid this complexity outdoors.
A friend suggested that I could use a Digitrax PM42 Power Manager, even though I'm running DC. He explained that the PM42 senses the short circuit as the train exits the reverse loop into the unchanged main line and instantaneously reverses the main line polarity for the train's return trip. This sound ideal. Will the PM42 work this way on a DC layout? Has anyone done this? Are there any potential problems? I note that MRC makes an AD-520 DCC Auto Reverse which seems to do the same thing at a lower cost, but the MRC website says the AD-520 can not be used on non-DCC or DC layouts. Does anyone know why MRC imposes this limitation? Thanks, Geezer