Germany's Stuttgart 21 project aims to create the first fully digitally-equipped railway hub in Europe.

The new Stuttgart Hauptbahnhof is now expected to open in December 2026, delayed from the initial target of December 2025.

The primary reason for the delay is the project's complexity in digitizing the entire railway junction.

The estimated cost of the project has surged to over 12 billion euros, which will be covered by Deutsche Bahn.

Challenges in planning and delivery, along with the project's complexity, are causing the delays.

The original phased opening and temporary signaling system plan has been scrapped due to cost concerns.

Transforming the old terminal station into an underground through station is a key aspect of the project.

The project's steering committee will provide more details on the revised timeline at a press conference.

Crucial elements like the Pfaffensteigtunnel and Gäubahn connection will be addressed in the press conference.

Deutsche Bahn has not commented on the latest delay; a press conference is scheduled for Tuesday to address the issue.