A plan to re-open a 170-year-old railway line to form a link with high speed rail and Birmingham Airport has gained Chinese backing.

China Railway Group has confirmed interest in rebuilding 7.3 miles of the Stonebridge Railway east of the city to link directly into the proposed HS2 Birmingham Interchange station. The line last carried passengers 97 years ago.

The scheme would cost up to £280 million and the Chinese firm has said it is prepared to finance it.

The proposals would mean a return for a route originally opened in 1839 between Hampton-in-Arden, near Solihull, and Whitacre Junction, in North Warwickshire, which closed in the 1930s.

The line would also link into the airport, National Exhibition Centre, and proposed UK Central economic development area.

The scheme envisages the restoration of passenger services from Walsall, through Sutton Coldfield, to Water Orton – raising the prospect of direct services to the planned HS2 interchange, near Birmingham Airport, without passengers having to change trains in the city centre.

While the funding presents a major boost, the plan will still have to win political support in the region, and China Railway Group has written to Birmingham City Council and the airport.

The scheme was drawn up by Alan Marshall, editorial director of Railnews, and specialist quantity surveyor and construction economist Michael Byng.

Mr Marshall told the Birmingham Post schemes like this were needed as passenger numbers increase and New Street station reaches capacity.

He said: “With the line restored it would be possible to run services directly to what would be the new HS2 interchange without going to New Street.

“We would anticipate that the service which hasn’t operated for a long time, from Walsall through Sutton Coldfield to Water Orton and directly to the new line, would be restored.

“It would give people from Walsall a link to HS2 without having to change anywhere. Currently, if you are travelling from Tamworth to the airport you would have to change at New Street and it takes 45 minutes. With this it could be down to 18 minutes.”

China Railway Group wrote to council leader Sir Albert Bore about the proposal on December 19.

A letter signed by the company president stated: “We have followed the publications prepared to develop Birmingham Airport and to improve the connections by public transport to it. We have also noted the comments made in the recently published Parliamentary Transport Select Committee report on HS2 railway line suggesting the need for additional rail links to its passenger hubs.

“Will you kindly accept this letter as our formal expression of interest in working with the public authorities, Birmingham Airport, and other stakeholders within the region to design, construct and finance this project.

“We write to express our formal interest in making long-term investments in the region, including investment the development and enhancement of Birmingham Airport, and in the development of the railways of the region to connect with the proposed HS2 High Speed line.”

China Railway Group, which is listed on the Hong Kong and Shanghai stock exchanges, is the principal operational subsidiary of the China Railway Construction Corporation.

Its interest comes just months after proposals for Chinese investment in plans for the high-speed rail link between London, Birmingham and Manchester were mooted.

It also follows Sir Albert’s mobility action plan for the city, which outlines aims to improve access to the airport due to complete a runway extension in April.

A Birmingham City Council spokesman said: “We are always keen to hear of any proposals that could improve connectivity and transport infrastructure in the city and believe that HS2 and any related works are key to this.”

Geoff Inskip, Centro chief executive, added: “This is an interesting proposal and more work is needed to understand exactly how it could improve access to HS2 and Birmingham Airport and deliver improved, direct journeys to and from the West Midlands.

“Our research reveals HS2 will bring 51,000 jobs and £4.1 billion per year to the regional economy, so we’re particularly keen to understand if this scheme can add to the economic benefits high speed rail will bring to the West Midlands.”

Under the plans, the Whitacre Link would have its own four-platform station alongside the planned HS2 Interchange.

These side-by-side stations would also be connected to a new international terminal where passengers could check in for train services to Continental Europe via the Channel Tunnel or for flights to anywhere in the world, served from Birmingham Airport.

Councillor Timothy Huxtable, who was previously cabinet member for transportation and regeneration at Birmingham City Council, said the proposals would make Birmingham Airport, and the wider UK Central area, more accessible throughout the Midlands.

Coun Huxtable (Con Bournville) said: “At the moment the East Midlands is relatively poorly served from Birmingham New Street. We have got the CrossCountry line going to Sheffield and Leeds via those areas, but that is it.

“Stonebridge Railway, or the Whitacre Link, would essentially link the Midland mainline to Birmingham Airport and will dramatically improve access from these areas.

“It would also be a lot easier for people from these districts to connect with the NEC, Birmingham Business Park and Solihull’s UK Central.”

Coun Huxtable said the proposals would represent additional value from wider plans for HS2.

He also said he was happy that funding was coming from China, as it would create local jobs.

He said: “The Government has worked out the benefit of HS2 in itself, but the benefits would be multiplied with local lines like the Whitacre Link.”

The plans were raised in Parliament in December by Christopher Pincher, MP for Tamworth, who asked: “Currently, the 15-mile journey between Tamworth and [Birmingham] airport takes 45 minutes by rail. Does he therefore agree that infrastructure projects such as the Whitacre rail link, which would reduce the journey time to 18 minutes, could be beneficial to my constituents and the airport?”

Transport Minister Stephen Hammond replied: “I am happy to look at the Whitacre Link proposals. I encourage my honourable friend to continue to discuss the development of the business case with the local enterprise partnership and Centro so that it can be brought forward.”

A recent study by Steer Davies Gleave found that 78 per cent of passengers who travel to the airport by rail have to change trains or stations in Birmingham.

An airport spokesman said: “We can confirm that a letter on this matter has been received by the airport. Any rail infrastructure development that would improve access to Birmingham Airport would be welcomed.”