British Steel will supply a further 4,000km of rail to Network Rail, after winning an extension to its existing contract.
The Scunthorpe-based manufacturer already had a five-year agreement to provide 9,000km of track – but today's announcement extends the deal by a further two years.
It follows a similar two-year extension to Transport for London's contract for the supply of London Underground rails.
The firm said its deal provides Network Rail with "excellent value for money", by supplying products which reduce the need for maintenance and replacement.
"This is excellent news, not only for British Steel but also the millions of people who use the UK's rail network.