The railway industry has been challenged to come up with a reasoned alternative to Sir Rod Eddington's vision of the future of transport in the UK.
Mark Lambirth, director of rail strategy and finance at the Department for Transport, said it had yet to set out exactly why it did not approve of Sir Rod's conclusions that small improvements to the network could be more cost-effective than big schemes like building a new north-south high-speed line.
He told the Railway Forum sustainable development conference that he had not heard whether it thought Eddington was right or wrong.
He said: "Something strange is happening here. Eddington published and the Railway Forum said it was disappointed but what I have not heard from the rail industry is something that says either 'his analysis is right but for the following reasons it is worth trying to attract air to rail with a high-speed line', or 'no we don't accept the analysis for these reasons'.
"That's the challenge for the rail industry. Eddington is said to be a disappointment but why is it reaching what the Railway Forum says is the wrong conclusion," he said.
He was responding to Railway Forum director-general Paul Martin, who said the Government had to start planning for a high-speed line now if it was to be in service in time to deal with growing capacity.