A £320 million rail link between Oxford Parkway and London Marylebone has opened.
The joint deal between Chiltern Railways and Network Rail is the train line to link a major city to London in 100 years.
The rail link will serve new stations at Oxford and Biecester Village.
The direct line from London Marylebone to Oxford will have a journey time of less than one hour, with a link to central Oxford complete in 2016.
It’s expected to attract an additional 250,000 return journeys a year.
“This is a rare example of new direct competition on Britain’s railways”, Chiltern Railways said in a statement.
The new service will offer two new fast trains per hour throughout the day between Oxford Parkway, Bicester Village Station and London.
Network Rail chief executive Mark Carne said the new line would help to boost capacity "as rail travel is forecast to double over the next two decades”.