Two refurbished platforms at Birmingham's Moor Street station are set to open to passengers - for the first time since 1987.
Chiltern Railways, which runs the station, said Moor Street can now become an established second hub for trains from Birmingham to London.
Company director Ian Baxter said the extra capacity meant greater flexibility for services.
The £13.5m development is part of the larger £250m Chiltern Mainline project.
Heritage and family specials will run on Saturday from the redeveloped section with regular services starting on Sunday.
The historic station, first built in 1909, has been undergoing renovation since 2003 when its Grade II listed buildings were restored.
The disused platforms were recommissioned last year and mean that Moor Street now has four platforms in use, doubling its capacity.
Chiltern Railways said the measures will help reduce journey times by an average of a fifth with a trip from Moor Street to London Marylebone taking just 90 minutes when the project is complete.
The planned completion date for the whole Chiltern Mainline project is May 2011.