Rail is supporting the construction of Sizewell C nuclear power station in Suffolk, in the east of England. The project involves upgrading the Sizewell Branch Line from Saxmundham to Leiston and constructing a temporary “Green Rail Route” into the main construction areas. According to the developers, this forms a key part of their strategy to deliver sixty per cent of construction materials via rail and sea, reducing pressure on local roads and lowering carbon emissions.
Work on the branch line includes track renewal, new signalling, and upgraded level crossings. This will allow freight trains carrying heavy and bulk materials to reach the site. The line last saw regular passenger services in 1966, but movements are expected to resume shortly. Network Rail and Sizewell C project teams are coordinating these works. The Green Rail Route itself is planned to bypass the village of Leiston to minimise traffic conflicts.
Temporary rail link to construction areas
The Green Rail Route is a temporary railway designed to bring freight directly to the designated Temporary Construction Area. Materials will be offloaded, stored and forwarded for use. The route branches from the existing Sizewell Branch Line and will be removed once the power station is built. Land will be reinstated. Work includes laying track, signalling, drainage, adding ballast and constructing new level crossings across the flat East Anglian land.
Temporary rights-of-way and footpath diversions are in place through 2026 to allow track laying and earthworks. Phase 1 involves early rail movements on the existing branch for work trains and deliveries. In contrast, Phase 2 will see additional freight trains, particularly at night, bringing construction materials directly into the site, helping reduce road traffic.
Upgrades to existing lines
Alongside the temporary link, the East Suffolk line is being upgraded to handle heavier freight alongside passenger services. Continuously welded track, signalling improvements and enhanced level crossings are being installed, bringing the branch line to industrial freight standards. Network Rail notes that forecasts indicate up to four round-trip trains per night could operate along the Green Rail Route once fully commissioned, helping achieve the project’s rail and sea delivery targets.
According to the project partners, significant material volumes will shift from road to rail. By improving both the Sizewell Branch Line and East Suffolk connections, construction logistics are expected to be smoother, with a reduced impact on local traffic. “The arrival of the first engineering train marks a major moment for the Sizewell C project,” said Damian Leydon, Site Delivery Director at Sizewell C. “As rail deliveries increase, we’ll continue to reduce our carbon footprint and minimise disruption to the community.”
Planning for legacy and post-construction use
Once Sizewell C is complete, the temporary Green Rail Route and associated construction infrastructure will be removed and the land reinstated. Network Rail says that the upgraded elements of the branch and East Suffolk lines will remain as part of the national rail network, potentially benefitting future freight or local rail services.
The Sizewell C nuclear power plant development is not without controversy. However, the railway development is proving less contentious. The project illustrates an intention to use rail to deliver large-scale construction projects sustainably.