Option 3: Electrical only

Some manufacturers offer ‘electrical only’ methods for switching the frog polarity. Dccconcepts makes the ADS decoder for solenoids, which has a built-in relay with SPDT contacts to switch the frog polarity in preference to a motor-mounted switch. This can be used for both DCC and analogue DC layouts. Or you could use Gaugemaster’s GM500 with relay switching in parallel with the solenoid.