If you are using the NCE Switch Kat decoders be sure to look at https://ncedcc.zendesk.com/hc/en-us/articles/200918205-Switch-Kat-for-Kato-Lemaco-or-LGB-remote-control-turnouts. They already have an indicator output. Then substitute in either one or two opto-isolators instead of the LEDs or incandescent lamps shown in the diagrams to indicate the last known turnout position . As other have said, then use the open collector output(s) of the opto-isolators to activate the input(s) of your favorite type of input device to get to Railroad.com software on your PC.

DonV  

Hi Folks!  I am new here and at age 81 decided to get into N scale.  What is the best way to feed turnout position info to Railroad.com software using KATO turnouts with NCE switch kat decoders?                                     
Allan