£45m has now been sunk into the redoubling of the Swindon to Kemble rail line as the ambitious project was finally completed during bank holiday weekend.

The infrastructure upgrade along the route included the reinstatement of the second line between Swindon and Kemble, improvements to earthworks to accommodate the new track, and the installation of new signalling equipment which will safely control the movement of trains.

The new infrastructure provides increased capacity, which will be crucial to meet future passenger demand and will reduce delays for a more reliable service.

These improvements will also be essential to enable trains from south Wales to be diverted along this route when Bristol Parkway station and the Severn Tunnel are closed for electrification work.

Simon Maple, Network Rail’s route programme and project sponsor, said: “Now that our work is complete, passengers can look forward to fewer delays and reduced journey times in the future. It also means we can minimise the disruption caused by our electrification work and ensure the region gets maximum benefit from a modern, electric railway.

“As is the case with most major works, a certain amount of disruption is unfortunately unavoidable and I would like to thank passengers and local residents for their continued patience and understanding.”

Other improvements incorporated as part of the upgrade project include the installation of additional signals between Kemble and Standish Junction, level crossing upgrades at Minety and Purton Collins Lane and the installation of a new footbridge in Stroud.

Rob Mullen, First Great Western’s general manager central, said: “These are vital infrastructure works to help pave the way for increased capacity and reduced journey times, and better performance and punctuality that electrification and new electric trains will bring for future services.

“We have worked closely with our colleagues at Network Rail to keep disruption to a minimum but I must thank our customers for their understanding and patience as we seek to make the improvements that we know they want to see.”

Alex Evason, senior construction manager at Swindon Network Rail, said extra services would not be seen straight away.

“Even though people may not see masses of new trains straight away, the network will have a new artery,” he said.

North Swindon MP Justin Tomlinson said: “This is the record amount of money put into the railway network since the Victorian times. It is unbelievably important for the economy, and really strengthens Swindon’s hand.

“It is all about driving up capacity, which just makes Swindon an even more attractive prospect for businesses to relocate to the town, creating jobs and prosperity.”