A huge countryside solar farm, set to be one of the biggest in the country, will generate renewable electricity to help power the rail industry.
Network Rail has struck a deal with the energy firm constructing the array to use electricity generated there to power its stations, offices and depots across the country.
The arrangement is said to be the first of its kind, with the rail minister Wendy Morton hailing it as a "huge moment" for the industry.
Electricity generated at the site deep in the Norfolk countryside, close to the London to Norwich main line, will be fed into the national grid and under the deal Network Rail will buy all the energy generated at the farm close to the village of Mulbarton.
The rail body estimates it will cover 15% of its power needs, excluding the electricity needed to power the trains themselves.
Construction on the 200-acre site, which is being built by EDF Energy, is due to start in early 2024 and be completed by the end of that year.
Jo Lewington, Network Rail's chief environment and sustainability officer, said: "Our vision is to serve the nation with the cleanest, greenest form of public transport and this agreement marks another important step towards achieving our aims."
When the scheme was approved in June there were some concerns about the plans.
Local councillor Florence Ellis said the UK needed land for food supplies as much as energy production and criticised having such a large project next to small villages.
Darren Cuming, on behalf of EDF, said the site was chosen to reduce the impact on the local community and promised the team building it would liaise with local residents.
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