TADDaemon
General
TADDaemon.exe is found in the "bin" folder and comes from Trainz Asset Database Daemon(=Service). This is the utility that maintains communication between Trainz Components.
It is used to validate Planet Auran Login details (username & password), to check if the serial number is genuine/registered and to download content from Download Station. You can see the TADDaemon window by enable Database process window in Trainz Launcher Advanced Options.
Technical Details
TADDaemon must be allowed through firewall because it has to connect to the internet and to communicate at OSI Layer 3 on localhost (127.0.0.1) with other Trainz Components.
DO NOT SHUT DOWN Windows before TADDaemon.exe has finished running! (check to see in Task Manager). Doing so, may lead to a corrupted Database which will be repaired at the next Trainz launch, which might make a lot of time.