I am reminded when I first started with Trainz, in T:ANE standard back in 2013 (HEY! I passed my 10th anniversary!). I was finishing one of the tutorials which meant switching into a yard, but the signal light would not change, and if I tried to run it the session would cancel because I was a bad boy. At that time, I posted here on the forums somewhere, and someone pointed out that you could somehow get information from the red signal about what other signal was causing it to stay red. I don't know if it was something with a right click, or how it worked exactly, but I was able to determine which junction had to be changed so that my signal would turn green, and I could proceed. Sorry I can't remember any more, but I am wondering if somehow you could use a similar method to see what is with the junction.