As to Quick Drive, the only current references I could find are to the QuickDrive Rule in the Session Editor. This is now a simple method of setting up the parameters in a session for Driver Mode (time of day, UI control method, units of measurement, restrictions on what the user can do). This function has changed during the development of Trainz. It used to be a rule that allowed users to place and remove consists while in Driver but this function was changed to the present list of functions with no ability to place or remove consists. This change appears to have occurred after TS2009 as I could find no references to it after that version. I never used Quick Drive as a means of placing/removing consists while in Driver so I have no real experience of what Ighten is describing.
Is it possible that you are using a Route/Session from TS2009 (or earlier) that may have the original (legacy) Quick Drive Rule?