The new operators of the East Coast Main Line (ECML) - which is currently being run in the public sector - will also have to demonstrate how they will support economic growth on the line between Edinburgh to London King's Cross.
The minimum criteria for the company that will ultimately run the line were outlined as the UK Government published the InterCity East Coast prospectus.
Potential bidders have been told to provide a "better travelling experience", though this is open to interpretation. It could include anything from wi-fi to leather seats or improvements to the buffet car.
The line has been run under the control of the Department for Transport (DfT) since National Express pulled out of the franchise in November 2009.
Labour and rail unions have bitterly opposed the reprivatisation of the line, pointing to the fact that East Coast has returned large amounts of money to the Treasury since it has been in the public sector.
TUC general secretary Frances O'Grady said: "The Government has completely lost the plot over its handling of our railways. Since returning to public ownership the East Coast line has flourished, with rising customer satisfaction levels and £800 million returned to the UK taxpayer."
A leaked document obtained by the RMT union has also revealed the prospectus includes suggestions for bidders such as the introduction of an "intermediate class" of travel, effectively bringing back third class on trains from Scotland to London.
Channel Tunnel high-speed train company Eurostar has said it wants to bid for the East Coast franchise in partnership with French company Keolis. Virgin, which operates the West Coast mainline is likely to submit a joint bid with Stagecoach, while First, which runs the Scotrail franchise, are also expected to be among the bidders.
Anthony Smith, chief executive of the independent watchdog Passenger Focus, said it would be "watching closely on behalf of passengers" and wanted to see their interests "put at the heart of all contracts".
Meanwhile, Labour's new shadow transport secretary Mary Creagh said she was open to the idea of renationalising the rail network, highlighting that a number of foreign state-owned railways - including Germany's Deutsche Bahn, France's SNCF and Holland's Nederlandse Spoorwegen - were involved in firms running the UK's network and using the money generated to improve services in their home countries.
The new operator will be expected to capitalise on Government investment in this route over the next six years, including the replacement of the current rolling stock fleet and infrastructure improvements.
The DfT plans to confirm which prospective bidders have passed the pre-qualification stage in January and expects to issue the invitation to tender in February. Shortlisted bidders will then have three months to prepare bids, with franchise services starting in February 2015.
Transport Secretary Patrick McLoughlin said: "We want to see a revitalised East Coast railway, one that both rekindles the spirit of competition for customers on this great route and competes with the West Coast on speed, quality and customer service."