The line improves access to Corfe Castle
The deadline has been extended for the Purbeck Community Rail Partnership to secure a £3 million funding pledge, so vital re-signalling work can take place.
It now needs to be found by April 2010 - originally February - so regular passenger train services can resume from Wareham to Corfe Castle and Swanage.
The service was withdrawn in 1972.
Funding is needed for essential track and signalling work.
Swanage Railway volunteers are urgently appealing to more than 4,000 members of the award-winning heritage line - as well as the general public, to lobby Members of Parliament, candidates in the forthcoming general election, central government and statutory bodies - to find and commit to the funding.
Strong local support
Dorset County Council and Purbeck District Council have been long supporters of the scheme.
Both authorities are part of the Purbeck Rail Partnership, which is a group of organisations with an interest in the restoration of the Wareham to Swanage passenger rail service.
It also includes South West Trains, Poole Borough Council, South West Regional Development Agency, BP (who have a depot at Furzebrook, accessible from the line) and the company that run the current service, Swanage Railways.
In December 2009, Dorset County Council and Purbeck District Council invested £50,000 each to pay for design work required to plan the update of the signalling and track infrastructure at Worgret Junction, near Wareham - essential if regular passenger services are to run between Wareham and Swanage.
The design work will be carried out by Network Rail, but £3m is needed for this to be carried out.
With the money Purbeck Community Rail Partnership will pay Network Rail in increments during 2011 and 2012, for the re-signalling and other works at Worgret Junction.
The junction is the start of the Network Rail line to Motala, just east of Furzebrook, and the start of the Swanage Railway tracks to Corfe Castle and Swanage.
Network Rail plans to re-signal the main London to Weymouth line between Poole and Wool during 2012.
If Worgret Junction is re-signalled at the same time it will cost £3 million, but if it is re-signalled at a later date it could cost up to £10 million.
Swanage Railway claims it had 224,000 passengers in 2009
Mike Whitwam, of the Swanage Railway, said: "We are very grateful to Network Rail and pleased that it has been able to give the Purbeck Community Rail Partnership a two-month extension.
"The new deadline will hopefully be sufficient to allow the Purbeck Community Rail Partnership to identify sources of funding and commit to paying Network Rail £3 million as it progresses with its main line re-signalling project."
The Swanage Railway contributes £10 million a year to the Purbeck economy with a permanent train service between Wareham, Corfe Castle and Swanage set to increase that local benefit.
Mike explained: "This is a once in a generation opportunity to right the wrong of 1972.
"We and our partners on the Purbeck Community Rail Partnership are devoting resources and energy to success, not failure.
"But we only have until the end of April to secure a pledge for the money.
"The Purbeck Community Rail Partnership and the Swanage Railway are working hard to try and secure the funding pledge - and have been for almost a year - but it is proving difficult because of the reduction in budgets by central and local government, as a result of the squeeze on public spending.
"Our eleventh hour appeal is aimed primarily at central government and statutory bodies - perhaps even any millionaires or National Lottery winners who would like to help give the people of Purbeck back their train service."
If the £3 million is not found, the Swanage Railway will continue to accept occasional charter passenger trains and other special workings, such as visiting locomotives and track maintenance trains.
But, those charter trains and other special workings will be in jeopardy when the existing infrastructure at Worgret Junction, dating from 1976, and the closure of the Victorian signal box built in 1884, comes to the end of its operating life and needs to be replaced.
The Swanage Railway is not contributing to the £3 million as it continues to invest a substantial amount - in the region of £500,000 - on improving its track and infrastructure to allow regular trains from Wareham to Corfe Castle and Swanage, in addition to the heritage steam train service, which carries 220,000 people a year between Norden park and ride and Swanage.
That development work includes a new signal box at Corfe Castle station, which will interface with the new Network Rail signalling centre at Bournemouth.
Network Rail have already planned to upgrade the signalling between Poole and Wool in 2012.
Securing the £3m now will ensure that additional signalling work on the branch line to Swanage can be carried out at the same time.
Work is carried out on the track outside Corfe Castle station
Despite strong local support, the project is competing with many other projects for funding, both nationally and locally.
Tim Westwood, Traffic Manager at Dorset County Council said: "There are many critical transport or infrastructure improvements needing funding, like Poole's Twin Sails Bridge, the A338 reconstruction, and the Weymouth transport package ahead of the Olympics.
"In a different financial climate we wouldn't be where we are, but one would have to admit that the Weymouth Olympic package is just as pressing [as the Swanage Railway].
"There was also talk of an under spend on the work on the Weymouth Relief Road, with the surplus being used to pay for the Swanage Railway - but there is no under spend.
"The plans [for the Swanage Railway] are on the desk of the Secretary of State for Transport [Lord Andrew Adonis] and it's his decision."
The Swanage branch line was closed in 1972, one of the last closures as part of the government's Beeching Report, which recommended a series of railway "rationalisation" measures.
But since then, teams of volunteers have worked to restore the line and it currently runs as a "heritage" steam railway from Swanage to Norden.
The final part of the line - the track linking onto the main rail network at Wareham - was restored in 2002.
In 2009 the first specially-chartered passenger train ran.
But the main aim has always been to create regular passenger services.
'A tremendous boost'
Julian Maughan, Swanage and Purbeck Hospitality Association
Julian Maughan from The Swanage and Purbeck Hospitality Association, a group of business owners who support the project, said:
"I think reconnecting to the main network rail infrastructure would be a tremendous boost to the local economy.
"It would enable visitors to get to Swanage in a much more environmentally friendly manner using public transport and relieve some of the burden on the county's already overstretched road network."
"But that requires significant investment of funds to do the necessary signalling work - but I can't see a better investment [in the area]."