[5] The concept attempts to combine plans for high-speed links from Stuttgart to other cities with the improvement of local infrastructure and replacement of the current terminal station.

Parts of the historic Bonatzbau building, the platforms and approach tracks are to be demolished, and the land sold for urban development.

On 2 April 2009, the Premier of Baden-Württemberg, Günther Oettinger, signed the finance agreement with the German Minister of Transport, Wolfgang Tiefensee and Deutsche Bahn board member Stefan Garber.

On 28 June 2007, a high-level conference was held and adjourned between DB chairman Hartmut Mehdorn, Baden-Württemberg Minister of Finance Gerhard Stratthaus and Stuttgart mayor Wolfgang Schuster.

On hearing the promise at the time, Alliance '90/The Greens candidate Boris Palmer withdrew his candidacy for the second round vote, recommending that his supporters should back Schuster instead.

[14] In October 2007, a petition and public demonstrations were started, sponsored by private individuals with the backing of Alliance '90/The Greens and a variety of citizens' and environmental organisations.

The petition gained 67,000 signatures[citation needed] but political wrangling began over whether the issue could be decided by a local referendum in the first place.

During the estimated construction time of at least 10 years, the project would cut off connections to other park areas of the city, known collectively as the Green U due to their U-shaped form.

In November 2009, members of the International Council on Monuments and Sites stated that the Hauptbahnhof was a building of exceptional quality, whose integrity should be maintained.

On 30 September 2010, hundreds of demonstrators were injured when the police used water cannon, pepper spray and batons against protestors.

[25] According to the German newspaper Die Welt, in June 2009 the Greens changed the balance of power in the city council as a direct result of disgruntlement with the controversial Stuttgart 21 rail project.

While the CDU again won the largest number of seats in the Landtag of Baden-Württemberg, they and their FDP allies lost too many to maintain control.