Deutsche Bahn announces that the partners of the Stuttgart 21 railway project signs a declaration on Monday for the planning and construction of the one billion euro Pfaffensteig tunnel between Böblingen and the state airport. Construction will start in 2026 and it will be operation in 2032. TBM method will be used.

https://www.stuttgarter-zeitung.de/inhalt.plaene-fuer-stuttgart-21-werden-geaendert-bahn-verspricht-tunnel-zum-flughafen-bis-2032.168d2e5c-681f-4028-985f-6abe1ef36936.html