@firsttimer posted:
...I cannot direct the power to Fixed In Two to run trains on that separate loop without first powering up Fixed In One to get the internal red light on, even slightly. ...
Correct. The TIU itself needs to be powered separate from your two loops. The TIU "steals" this power from Fixed In One. Or, you can apply TIU power via the AUX POWER INPUT jack on the side of the TIU using a 12V, 15V, etc. wall-wart which you might already have in a box...otherwise they are maybe $5. Powering the TIU in this way keeps the "internal red light on" all the time so that you can independently operate DCS on your 2nd loop.