Hi Mvek,
Trains don’t go where its free, they have a defined path. If you want to change their path use waypoints not signals. Signals are only to avoid a crash (or in this case, avoid trains being stuck facing each other).
Unfortunately the rail network part of the guide will probably never come. Because since today I never being able to create a huge network due to lost of saved game each time the game update. That has being fixed with the new system mod, and now I finally have a big complex network. Problem now is that the performance is so bad I have no motivation to play. I can only put the camera facing down and zoomed in. Otherwise the game freeze. And I have a computer with specs to play GTA V.
I can’t grow my network like this. All I did was connect all cities in the map and make 1 route to deliver goods in 5 towns. That’s it, now unplayable.