How Do I Script Junctions?

Hey I am a Train Enthusiast And I Build A Lot Of Railway Lines.

A Major Issue I have is I have 2 tracks, 1 goes one way the other goes the other. I Am starting to come up to stations with 3-8 Platforms. What I need is a script and some help with a Junction that is Automatic and when a train hits the sensor the junction changes so the train goes into another platform so that it doesn't hit another train. I have seen this before but the guy who did it unfortunately left roblox. His username was MAGICMOVIESTEAM1 .

Please Help Guys.

Thanks Very Much