The work has a potential value of more than £200m and will be delivered between 2019 and 2024, although some early works start in 2018.
The framework consists of mechanical and electrical engineering services, building services and fabric works on a wide range of Network Rail infrastructure assets in the south of England and in Wales.
SSE Enterprise Rail is a subsidiary of the Scottish energy company SSE. It has secured works in the Wales region which covers both the North and South Routes, and will use its new Taff Wells offices as its headquarters for all Welsh operations.
Western region works comprise of both the West Country and Thames Valley routes. SSE was also successful with bids for the Wessex route and London North West, where it will complete works on both the North and South routes.
SSE Enterprise Rail director of operations Tom Smith said: “Competition for the work was incredibly strong. The contract underscores our team’s exceptional skills and capabilities and our exclusive geographical presence in UK rail – with 3,500 people available across 62 office and depot locations UK-wide.”
Managing director Raj Sinha added: “Our rail offer continues to grow stronger and, with a turnkey service incorporating financial support, design, deliver/build, maintenance and asset ownership, SSE is ideally placed to offer a very different strategic perspective and delivery system to support the rail industry.
“This contract reinforces our clear intent to become a supplier of choice on Britain’s railways and signals how proficient we have become in this field of work.
“With other strong opportunities on the horizon, we are working collaboratively to identify and deliver value-adding solutions through initiatives such as asset/project funding, asset ownership and alliances with Network Rail and other organisations including HS2 and Transport for London.
“We believe we have something truly unique to offer the industry and this contract award, we anticipate, will be the first of many significant initiatives we will be actively involved with over the next five years and beyond.”