Modernising the Core Valley Line

The design work for one of the biggest railway engineering projects of its kind is being undertaken by Amey Consulting in Wales right now – the upgrade of the ageing infrastructure of the Core Valley Lines (CVL). Delivered as part of Amey Infrastructure Wales’s (AIW) contract with Transport for Wales (TfW) to transform the Wales & Borders rail network, the £750m programme is a technically challenging series of work that demands a smart approach to maximise value and minimise costs.

The end goal is to create a metro-style rail network for the Cardiff region using with two new train fleets and faster journey times. Four trains an hour will run to every CVL valley head. The upgrades will also see improved station facilities and cut carbon emissions.

Electrification is a key aspect of the work which is a particular challenge, given the age, condition and history of the infrastructure. For example, the network has around 60-70 old bridges which are too low for live overhead lines to pass safely through. However, demolishing and replacing the bridges, as well as possibly lowering the track, would be a huge undertaking that would delay the project and could cost millions of pounds per bridge.

The Keolis Amey concept, being designed by Amey Consulting, is to circumvent the clearance problem by installing permanently earthed sections (PES) of overhead line at the affected bridges – a solution made possible by the hybrid nature of the new rail vehicles. Both new train types have the capability to switch between external electricity and on-board batteries, allowing them to power through the earthed section, even stopping and restarting at stations, before reverting to live overheads beyond the earthed section.

The CVL Transformation also includes modernising the signalling and construction of a new integrated control centre, re-doubling single-line track sections, remodelling critical junctions, upgrading stations, and ensuring the railway is accessible and inclusive by providing step free access at all stations and level boarding from platform to train. All the works have to be sympathetic to the environment and the communities alongside the track.

Nathan Sealy, Systems Integration Director for Amey, said,

“We’re overcoming some tough engineering challenges by working as a collaborative team with the contractors, the AIW programme and engineering management “PMO” and Transport for Wales and pursuing some exciting solutions to ensure best value for money. It’s taken us a long way – so far we’ve completed the outline design work for the first phase of the project (around two-thirds the total), are producing detailed design for construction work happening this year including track, stations and OLE, and are well into the outline design for the second phase.. There’s still a lot to do, but we’re on course to complete the CVL programme by 2024. We’d like to think it will be seen as an exemplar piece of work by the rail sector and Welsh construction.”