Late last week it was the turn of the national audit office. Its confidential report, alleging neglect of track, had found its way into the papers - "just by accident", Deutsche Bahn's chief executive wryly noted.

"If there's anyone in Germany interested in a good network, it is Deutsche Bahn," he said. "This is our business and we're not about to wreck it - even if some bureaucrats claim that we are. There are no safety deficiencies."

The Bundestag is meant to give its backing to the sale plan in the autumn, in spite of qualms about the tracks not being run by the state.

For Mr Mehdorn, the audit office joins the litany of doubters - politicians, rivals and consumers - he has had to fend off in his seven years at the helm.

The government recently accepted his main demand - that DB be allowed to run the track that DB and its rivals use - although it said the state would remain the legal owner.

Berlin is still working on the documentation, but Mr Mehdorn said he was almost certain the privatisation would take place. Public officials, though more cautious, also wager on success.

"That's because there's no alternative to the project," Mr Mehdorn said. "Berlin has enough problems with funding education, pensions and healthcare. Railways are not a priority. That's why the Bahn must fendfor itself."

Management had done its bit to ensure privatisation, he said. "We've made the Bahn fit in terms of profitability and efficiency."

Even his many commercial rivals and political foes would find it hard to deny that claim.

Since taking over in 1999, Mr Mehdorn has turned DB from a loss-making national railway into a profitable global logistics group. Operating earnings hit €2bn ($2.6bn) on sales of €30bn in 2006, DB's fourth straight year in the black.

Privatisation is meant to free it to grow even more.

Mr Mehdorn said eight logistics groups, including DB and Deutsche Post, held only 10 per cent of a global market of €500bn in annual sales and "50,000 other groups] hold 90 per cent".

He added: "It's a business screaming for the big guy to eat the little one - and we want to take part ... We could buy railway assets in eastern Europe or ... logistics assets in Asia or the Americas."

Because the German constitution demands the state controls the nation's rail lines, only 49 per cent of DB stock could be sold. People close to the company expect no more than half of that to go on the block at first.

"We don't expect to sell [DB stock] in the form of 'people's shares'. That chance has been botched," Mr Mehdorn said, referring to the initially popular Deutsche Telekom shares and their recent fall from grace.

Instead DB expects pension funds and other institutional players to be liningup to buy.

"A small portion of stock might be sold to retail investors," Mr Mehdorn said. "We need traded shares to get a market valuation."

That would also give investors an exit route, an argument against selling directly to private equity, he said. "Our owner has to decide . . [but Berlin] would get more via a stock listing as investors would be more willing [to buy]."