The contractor is an engineering partner of choice for Network Rail, Transport for London, Siemens, Northern Rail, West Midland Trains, Stadler, CBRE and multiple Tier 1 contractors such as VolkerFitzpatrick, AmcoGiffen and the Buckingham Group.

It has an annual turnover of £22m and a workforce of around 400.

1stinrail Managing Director Stephen Jackson, who will continue to lead the business, said: “The acquisition of 1stinrail by the RSK Group is a significant step forwards in our original vision to become one of the UK’s leading track contracting organisations.

“As part of this plan, it is essential that we provide our clients, when required, with a multidisciplinary end-to-end solution to their needs, as well as being able to assist them with expert advice and support across a much wider range of technical and operational requirements than just p-way.

“We are delighted to become a member of the RSK Group to both strengthen our current capabilities and be part of an established group of companies and personnel with a wealth of experience and capabilities in such sectors as design and engineering, environmental management, ground investigation and remediation, transport planning, civil engineering and building work.

“This will not only enhance our service offering to our existing clients but also enable us to grow and develop throughout the industry.”

RSK Group Chief Executive Officer Alan Ryder said: “This is an important acquisition of a business boasting a range of skilled professionals and an excellent reputation with its clients.

“1stinrail makes a significant contribution to our ongoing strategy of expanding our presence and capability in the rail infrastructure sector. 1stinrail will enhance the RSK Group offering and range of skilled and complementary services to clients in the wider rail sector.

“As RSK continues to deliver its ambitious growth strategy, it now comprises more than 175 companies, employing 11,000 people. The group’s annual turnover at the end of FY22 was £796m.”