Tracks won't stay connected to mainline 🤷‍♂️

So every time I build a station and connect the tracks to the main line once I leave my city and return right where they connect there's no connection and I have to rebuild the tracks time and time again. Because the tracks aren't connected initially I can't dispatch any trains so that I have to go again and rebuild the track so that I can read dispatch trains again. I'm losing time and I've missed out on several bonuses because of it. Is anyone else having the same issue.

Image number one below is how I built it an image number two is where it got disconnected on the left side.