The deal gives Balfour a business that designs, manages, installs and commissions railway electrification systems and services.
The business operates in the UK, Italy, Greece, the Netherlands and Portugal.
Its main customers are the Italian railway’s high-speed division, the Portuguese city of Porto’s transport authority and the Greek state railway company. Turnover is expected to be about £60m.
The ABB deal reflects the increasing importance of rail work to Balfour.
Chief executive Mike Welton said turnover from fixed rail infrastructure projects, which includes electrification, was estimated to be £800m a year – about 30% of sales.
He said: “With investment in rail infrastructure on a steady upward trend, Balfour Beatty’s many strong market positions and world-recognised technology put us in an excellent position for growth.”