Ok. I imagine all trains behind me will not pass by if I'm stopped on the slow line or maybe if I terminate my service they might pass me on the fast line. If they are routed on the fast line that is.
Honestly I couldn’t say for sure but I do believe that even if you are on the slows your train will still take priority over fasts
I just tested this at Gillingham. If I spawn a train on plat 1 and don't set a path, trains will continue to pass my train. If I set a path for my train then no trains will pass. If I delete the path then trains will start to run past me again. I tried the same at Newington and as long as I have no path set, trains will past me on the fast line. You could call this quick drive in a way. Very happy with the result. Thanks for you input bud.
I've been experimenting with this today and I believe the dispatcher does a rather good job! considering I'm adding phantom services here, there and everywhere. Finally the game becomes quite interesting.