Amey will use its High Output Plant System (Hops) to install and test 25kV electrification equipment, and will also be responsible for all foundations and structural steelwork on the Maidenhead - Bristol/Cardiff, Reading - Newbury, and Didcot - Oxford lines, a total route length of 378km.
Amey will also be responsible for planning electrification works and maintaining the equipment. The company and its supply chain will recruit and train 150 staff for the project.
The GWML is being upgraded and electrified under a £5bn modernisation project which includes the installation of ERTMS, reconstruction of the station and junctions at Reading, and the introduction of new trains.