two sources:

1. The official website of the project (Ministry of Transportation) has many resources (especially videos and maps) showing the exact future route of the train in many sections.

2. I live and commute next to the construction project, so whenever I see new changes or new information in real life regarding how and where the construction is happening, I update them on the map.

Of course this information is not guaranteed to be 100% accurate, but as of today it's the most accurate there is on this project.