Like I said: one point. The junction ability doesn't pay any extra points on the first time you touch the station. It just means that you get the points every time you touch the station, and not just once, like usually.
Quoting from the Okazu rules: "You get points for every time you connect a
string to this station tile." It's that simple.
To amplify this point, just read the very good Okazu english rules.