It's "needed" to increase throughput.
The current head station is a head station meaning it ends here and then they do a U-turn and go back different direction.
Also it's planned as a fully digital station which is supposed to increase the throughput as well as the trains can be dynamically throttled when enetering the station.
It's like any budget planned in Germany (or the world) for mega projects like this.
But I can understand that considering this is (according to the guide) basically a full concrete-slab and cube underground made in basically one pour.
Not done and still in construction but I could see it being done by 2030 (at least so trains can fully drive through).
More pictures: https://imgur.com/a/8QnDQrO
(Disclaimer: The descriptions could be wrong for the east/west orientation :P)
It's interesting to see it from the inside. It has been in construction for as long as I've leaved here. It looks like the inside of a mother-ship of some alien species.
Of course there is a lot of controversy about this project. I feel rather neutral about it.
Same here. The tour was interesting and the offer to see what could not be seen or done easily (like entering the train tunnel) was something I couldnt pass.
But the things that happened before this is not something what should be forgot.