POTENTIAL train operators have been told to provide at least two off-peak trains an hour between Bognor Regis and London.
Government officials have set out the minimum standard of service which the successful company will be expected to provide under the new franchise.
This also includes the number of trains from Bognor to Barnham and on to Littlehampton as well as occasional direct services to Brighton.
The details, which specify the arrival times of the first and last trains, are included in the invitations to tender which the government’s Department for Transport issued last Thursday.
The invitations set out detailed proposals of what the winning firm has to deliver around the clock if it wins the franchise.
Rail minister Simon Burns said: “Rail franchising has been a force for good on our railways and the department has been working hard to roll out its new franchising schedule.
“These are the first invitations to tender to be issued since the independent Brown review into rail franchising, which endorsed the government’s approach to the railways.
“We are now looking for innovative bids that provide value for money for taxpayers and put passengers right back at the heart of our railways.”
The services for Bognor are included in the Thameslink, Southern and Great Northern franchise. Five companies have been cleared to bid.
They are current operator Govia and its Southern subsidiary as well as Abellio, First, MTR Corporation and Stagecoach.
The successful bids are expected to be announced next May. The Southern franchise should start by July 2015. It will last for seven years.