You could have low dcs signal on track 2. However I'm not really sure how the crossover is wired when it comes to the center rail. Are both loops actually insulated from each other?
Place a lighted car on track 2 and remove the power supply to track 2.
Does the car light up?? is track 1 also supplying power to track 2 via the crossover.
One other thing... The tiu needs a power supply to fixed 1 or an aux power supply to function. (turn on. light up)