Today I released V5.0 of my PC based Remote Train Control program that includes WiFi support for the WIU/TIU and the WTIU. I'll be posting more about it over the next few days but you can visit these web pages for more information now.
The program is free and open source can be downloaded from my web site.
About the program in general and its history over the last 10 years:
http://www.silogic.com/trains/RTC_Running.html
About the newly added WiFi support: