Passengers travelling between Norwich and London have been told to expect better reliability and fewer delays when an old railway bridge in the city is replaced later this month.

The bridge, which carries the main line to London over Long John Hill in Norwich, will be demolished and replaced during the August bank holiday weekend, as part of Network Rail's Railway Upgrade Plan, to provide a better service for passengers. The rail line will be closed between Norwich and Ipswich while the work is carried out although to reduce the impact on passengers, Network Rail workers have already built the new and improved bridge on adjacent land.

Once the old bridge is demolished, the new one will be lifted into place using similar self-propelled modular transporter machines that transport NASA rockets.

The new structure has a flat and reinforced underside instead of an archway, to reduce both the likelihood of a vehicle hitting it, and the damage to the bridge if a vehicle does hit it.

Richard Schofield, Network Rail's route managing director for Anglia, said: 'Replacing this bridge will make the railway more robust and reliable, improving journeys for thousands of passengers, and the work has been planned to minimise disruption.'

Jamie Burles, managing director, Abellio Greater Anglia, said: 'The improvements will help to deliver a better and more reliable service for passengers on the Great Eastern Main Line. We are committed to working with Network Rail to improve punctuality and performance across our network.'

Following its deterioration over the years, temporary works were carried out to the old bridge last year so that trains could continue to use it, subject to a speed limit, to minimise any further damage to the structure.

Once the new bridge is in place, trains will once again run at line speed, resulting in fewer delays to passengers. Further work will take place underneath the bridge once it is in place so that the road and footpath can reopen in the autumn.

The work will take place from Saturday, August 27 until the early hours of Tuesday, August 30 and the railway will be closed during this time.

Passengers travelling between Norwich and London Liverpool Street will be affected by the closure and a rail replacement bus service will be operating between Norwich and Ipswich. Tickets will also be valid via Cambridge.