New trains, more services and fewer delays will transform the Southend Victoria branch line from 2020, as work is underway on a £46m upgrade to replace the overhead wiring system.

The existing wiring system, which was built in the 1950s and is the oldest in the country, is being replaced with a new system that will be more reliable, adapts to temperature and will mean fewer delays for passengers.

Network Rail’s Team Orange has so far installed 220 structures, which will carry the new wires, between Shenfield and Rayleigh. A further 166 structures have been installed between Rayleigh and Southend during weeknight shifts on Monday, Tuesday and Wednesdays. The remaining 144 structures will be replaced over the next year.

Between Shenfield and Wickford, nearly 12km of new overhead wire has been installed. A total of 128km will be installed along the whole line.

Once complete, the line will be much more reliable and enable more services to run.

Residents have raised concerns of sleepless nights while the works take place.

Richard Lambourne, chairman of Rayleigh Action Group, was confused as to why the works are taking place now.

He said: “Everybody wants the line to be upgraded but nobody expected the control depot to be based in Rayleigh. We have had months and months of replacement buses and works being done for Crossrail, so why was this not done at the same time?

“We are now going to have residents unable to sleep due to the works and that is unacceptable.”

Meliha Duymaz, Network Rail’s route managing director for Anglia, said: “We have made huge progress on our upgrade of the Southend Victoria branch line, which will improve reliability and meet future passenger demand as part of our Railway Upgrade Plan. When complete, this project and the introduction of the new trains will herald a complete transformation of the line from what it is today. We understand that the work affects journeys for those who are traveling late, and we thank passengers for their patience.”

Jamie Burles, Greater Anglia managing director, said: “We’re sorry that customers’ journeys are inconvenienced by this engineering work. However, this work is necessary for the modernisation of the railway in East Anglia, and will mean that our brand new trains, due to come into service from next year, will be able to run on a much more reliable set of overhead wires. By the end of 2020, when all of our new trains are in service, the Southend Victoria railway will have been transformed.”