It was reported on Saturday that the Deutsche Bahn rejected the project back in 1994, saying it could not be justified on economic grounds.
Der Spiegel reported that an internal paper from the Bahn's board concluded that the project would not be worth it even if favourable conditions were factored in.
Head of the Baden-Württemberg Social Democratic Party Nils Schmid called on Friday for the demolition work to be halted while a referendum be held to allow residents to vote on the matter.
His party, which is not part of the state government, moved on Wednesday for a legal manoeuvre to be undertaken to enable a popular vote – an amendment to stop the project would have to be introduced into the state parliament and then be allowed to fail to activate a referendum.
Schmid told the crowd on Friday night, he and the SPD supported the project, earning boos and whistles, but added that he wanted a vote on the matter.
“If one has good arguments, one does not have to hide them and can put themselves to a popular vote,” he said, with an eye on Baden-Württemberg state premier Stefan Mappus of the Christian Democratic Union, and justice minister Ulrich Goll of the Free Democratic Party, who have rejected proposals for a legal examination of the referendum idea.
Schmid promised that should the current state government refuse to organise a referendum, the SPD would hold one if it were to form part of the government following the March 2011 state elections.
Meanwhile, Deutsche Bahn head Rüdiger Grube refused to rule out the possibility that costs for the €4.1 billion project could rise.
“One can never say down to the last penny with infrastructure projects,” he was quoted as saying in the Wirtschaftswoche magazine on Saturday.
He blamed high safety standards for the uncertainty in cost projections.
“Ten years ago one had to build a safety exit every 1,000 metres, now it is every 500 metres,” he said.
But he added the figures were fundamentally correct, with the new Stuttgart station costing around €4.1 billion and the new stretch of line between Wendlingen and Ulm costing around €2.9 billion.
Grube also said further investment was planned to increase and improve the track network for goods transport, to cope with the expected doubling of traffic over the next 20 years.
And he said he would be launching a new communications strategy this month, with better information for passengers particularly in the case of service interruption – while the amount of information announced at stations would be streamlined.
In-train announcements will have less English-language information in the future, while station information will have more, he said.
He would also not rule out further price-rises accompanying the new timetable, to be announced in December.