Rail chiefs have ordered a review of proposals for a new Birmingham Grand Central Station to take the strain off New Street.
Network Rail is to conduct the investigation as part of a wide-ranging inquiry into rail capacity in the region.
But a Network Rail spokesman last night insisted it was committed to a planned #500 million revamp of Birmingham New Street, a scheme known as the New Street Gateway.
Various proposals have been put forward for a brand new station, following concern that it may prove impossible to increase capacity at New Street to meet the region's needs in the long term.
One scheme, drawn up by Birmingham surveyor Murray Rayner, would involve a site just to the east of New Street around Curzon and Fazeley streets.
Now, the New Street Station Working Party, which includes representatives from the Department for Transport, Network Rail, Birmingh am City Council and Advantage West Midlands, has decided that the option of a new station must be considered.
Network Rail will look at how large the station would need to be, how much it would cost and how it would affect the role of New Street.
However, the review is partly designed to reassure the Department for Transport, as well as potential critics, that every option has been considered.
Network Rail remains committed to the #500 million New Street Gateway scheme would involve the complete redesign and redevelopment of the station and surrounding area. This would increase passenger capacity, create more attractive platforms, add an enlarged concourse three and a half times bigger than the current space.
A spokesman for Network Rail insisted last night: "New Street Gateway is the only scheme on the table and is the one we are taking forward."