The government is finalising plans to transform the Great Western mainline as part of a drive to reduce carbon dioxide emissions from transport. The programme will involve installing hundreds of miles of electric cables as well as alterations to tunnels, bridges and stations on one of Britain's oldest rail routes.

An announcement could come as soon as Thursday, although the financing is still being put in place. The Department for Transport (DfT) and Network Rail, owner of Britain's rail infrastructure, have discussed electrifying the route from London Paddington to Cardiff, taking in Reading and Bristol, as well as the popular commuter route from London to Oxford.

However, the programme is expected to be carried out in phases over the next decade in order to minimise disruption.

Britain lags behind many of its European counterparts in electrical coverage of its rail system, with only 40% of the 20,000-mile network electrified. Lord Adonis, the transport secretary, has pledged to electrify swaths of the network, led by Great Western and the Midland mainline from St Pancras to Sheffield, in order to reduce carbon dioxide emissions from transport by 14% by 2020.

Train operators said electrification would bring quicker and more reliable services for passengers, as well as giving rail a green edge over car and air travel. Michael Roberts, chief executive of the Association of Train Operating Companies, said: "Electrification brings with it the dual benefits of helping to make rail services more attractive to customers and drawing them away from cars and planes. It also relies on lower-carbon sources of energy." First Great Western, the main operator on the Great Western network, carries 84 million passengers a year.

According to Network Rail, the diesel trains that travel on the Great Western route emit at least double the carbon dioxide output per mile of an electric train. The government-backed company has also calculated that it will cost £800,000 a track mile just to erect the cabling. Once work on tunnels, bridges and culverts is added in electrifying the 118-mile stretch from London to Bristol could cost £380m, according to Network Rail.

It is understood that the DfT and Network Rail have discussed funding the work through an increase in Network Rail's borrowings. Network Rail's debt is underwritten by the state and the government will pay off the interest over a number of decades, minimising the immediate impact on the taxpayer.

Stephen Glaister, professor of transport and infrastructure at Imperial College London, said the benefits of electrifying thousands of miles of railway track would be undermined if trains were not powered by energy produced from low-carbon sources such as nuclear plants or wind farms. Otherwise, electrification would simply increase demand for electricity from coal- and gas-powered plants, he added. "The government has to clarify where the electricity is coming from. In a world where nuclear power is declining and renewables cannot fill the gap, where else is it going to come from apart from burning more coal and gas?"

Lord Adonis, the transport secretary, said last week: "Transport accounts for a significant amount of our domestic emissions. Therefore decarbonising this sector has to be front and centre of efforts to meet our obligations and commitments to tackle climate change."

The government is also encouraging greater production, and acquisition, of electric and hybrid cars as part of its low-carbon policy.

See also:

Railway line 'to be electrified'

BBC News: 22 July 2009

Electrifying the London to south Wales line would be done in stages, the Guardian says

There are reports the rail line between south Wales and London is to be electrified, with an announcement possible as early as Thursday.

Last week a report by Welsh MPs said electrification between Swansea and London should be a top priority.

The Department for Transport said it planned "shortly to set out plans for a major programme of electrifications".

The Guardian newspaper claims the UK government is "finalising plans" to electrify the Great Western mainline.

The report said this would be part of a drive to reduce carbon dioxide emissions from transport and would involve electrifying the route from London Paddington to south Wales, including Oxford, Reading and Bristol.

I'm 60 soon and I have my doubts whether I will ever travel on an electrified train all the way through to Cardiff
Rail expert Christian Woolmar

Welsh Affairs Select Committee said it would also lead to significantly better and faster services for passengers.

The Department for Transport (DfT) responded to the committee's report by saying it had been "working closely" with the Welsh Assembly Government "to examine the detailed case for electrification of the Great Western main line between London and Swansea".

The Guardian claimed the electrification of the line would be staged over the 10 years to 2020 to minimise the delays and disruption it would bring.

'Wet and damp'

But rail expert Christian Woolmar downplayed the idea of an electrified rail line reaching south Wales any time soon.

He told Radio Wales: "There has been talk about this for years and years, but hold your horses, it's not going to happen instantly.

"Probably this will to be carried out in stages. There would be initial electrification to places like Newbury, effectively London suburban trains.

"Then they might do it to Bristol and eventually through to Cardiff but possibly Swansea, then maybe right to the end of the line, who knows?

"But that's really way ahead and there is a big obstacle, of course, between London and Wales, and that's the Severn Tunnel.

"It's pretty wet and damp in there and there might not be enough room to electrify it without digging out the tunnel somewhat, so it will be a big barrier.

"I'm 60 soon and I have my doubts whether I will ever travel on an electrified train all the way through to Cardiff. But I might travel on the [electrified] London suburban network."

A DfT spokesperson said: "As we made clear in the document 'Building Britain's Future, as part of our continued shift towards low carbon modes of transport we plan shortly to set out plans for a major programme of rail electrifications."