THE cost of bringing a rail passenger service back between East Oxford and the city centre could be more than £450m.

Chiltern Railways last year announced its ambition to open the old Cowley Branch Line – currently used by BMW for freight – to passenger services by 2020.

The scheme is seen as key to tackling the city’s chronic congestion problems and would serve Oxford Parkway in Water Eaton, Oxford Station, Oxford Science Park in Littlemore and Oxford Business Park in Cowley.

It would also link East Oxford to services to London.

But rail bosses said more track space was needed between Oxford and Didcot, as well at Oxford Station.

Chiltern Railways director Graham Cross said the tracks were key to bringing back passenger services on the Cowley Branch Line, as there was not enough capacity between Oxford and Kennington, where trains would join the reopened line.

A report by Network Rail said increasing the number of tracks from two to four on the stretch would cost between £175m and £375m, with the cost of Oxford Station’s redevelopment put at £75m by councils.

Mr Cross said: “We see the Cowley Branch Line as an exciting proposition and a good answer to a lot of problems Oxford has with road congestion.

“A capacity increase would open the door for the Cowley Branch Line and allow us to run Chiltern trains between Oxford Station and Kennington junction.

“It is at the options stage at the moment, but there is a wide consensus in the rail industry that it is the right thing to do.

“Upgrade work would also be needed on the branch line itself, because at the moment it is just used by freight.”

He added the firm did not yet have cost estimates for building the new stations.

Additional costs for upgrading the branch line have also not yet been estimated.

Passenger trains stopped in 1963 after British Railways withdrew its Oxford to Princes Risborough services.

Oxfordshire County Council leader Ian Hudspeth said he was “very hopeful” the line could be resurrected.

The branch line has been included as part of the authority’s proposed new Oxford Transport Strategy for up to 2031.

Mr Hudspeth said: “The Cowley Branch Line could bring huge benefits to Oxford, because it would allow people from Bicester, Banbury and West Oxfordshire to reach East Oxford more easily.

“It is a scheme that could really open up key locations in the city, many of which can only be reached by driving at the moment.”

He added: “We will be lobbying for this as a priority with the local enterprise partnership.”

The option of increasing the number of tracks between Oxford and Didcot has been put forward in Network Rail’s Western Route Study.

It is being considered because the firm has predicted Oxford North Junction – a rail junction near Trap Grounds – will be at maximum capacity by 2019, as will Oxford Station.

The Western route study said nine trains per hour are expected to pass in each direction through Oxford by 2019, plus an additional two during peak hours. Two to three freight trains per hour are also expected.

The study said: “Any increase in the number of services... would require a comprehensive infrastructure intervention.”

One option being considered is raising the number of tracks between Oxford and Didcot from two to four, redeveloping Oxford Station to add extra platform space, and building a railway flyover at Didcot East Junction.

Network Rail said that would “potentially eliminate” capacity issues at Oxford and offer “operational flexibility”.

Spokeswoman Victoria Bradley said the firm’s final proposals would be published within the next three months.

They will be part of its wider strategy for 2019 to 2025, and will seek funding from the Office for Rail Regulation.

Oxford City Council has backed the redevelopment of Oxford Station, as well as plans for the Cowley Branch Line.

Earlier this month it suggested the route could be served by trams or light rail.

City council leader Bob Price said: “The Cowley Branch Line is one of those things that makes so much sense and has long-term benefits.

“But putting extra tracks in will cost many millions of pounds and Network Rail will have to be a key player in that.”

A Department for Transport spokesperson said: “We know how important the railway is for the economy and for passengers.

This is why we have embarked on one of the biggest programmes of modernisation on the network for a generation. We are working with local authorities and the rail industry as proposals for the Cowley branch line are developed.”