Client: Amey The Core Valley Lines (CVL) transformation is a £740 million project forming part of the wider South Wales Metro initiative. It includes major infrastructure upgrades, such as overhead line electrification across large sections of the network, platform extensions to accommodate new trains, and the refurbishment of several stations. The project also involves constructing a new depot at Taffs Well and renewing extensive sections of track to improve network reliability. As a key element of the South Wales Metro, these upgrades will enable more frequent, greener, and faster services, transforming connectivity for residents and supporting sustainable urban growth. Services we provided Rail Engineering Civil & Infrastructure Engineering Our Role BWB was heavily involved in the Core Valley Lines project, providing a range of professional services directly to the client. Our team contributed to the design of new track and line-side civils as well as outline (GRIP4) track designs for the Rhymney branch of the South Wales Metro system. Civil engineering Our civil engineering team supported the double-tracking of over a mile of route between Tir-Phil and Pontlottyn, and the track lowering at Llanishen, to facilitate Overhead Line Electrification (OLE) works. Value engineering The project’s scope and complexity required careful budget management and stakeholder collaboration. BWB’s team worked closely with multiple stakeholders to ensure that the design met their varied needs while minimising budgetary impacts. High standards We also provided line speed increase designs through Cardiff Central Station and delivered a detailed (GRIP5) bridge waterproofing design at Aberdare. Our ongoing support throughout the construction phase helped ensure that the infrastructure was delivered to the highest standards.