Why a South Wales rail transformation programme impressed the APM Awards judges

The Core Valley Lines transformation programme by Transport for Wales (TfW) shows what outstanding project management can achieve.

South Wales is a region of many contrasts. Cardiff has an increasingly vibrant economy, with an expanding population and the highest GDP in Wales, but the neighbouring post‑industrial region immediately to the north – the former mining country, which includes the Rhondda, Cynon, Taff and Rhymney valleys – is home to some of the most economically deprived towns and villages in Europe.

Enter the Core Valley Lines programme, which scooped the 2024 APM Overall Project of the Year Award. It is a £1.5bn programme with a grand vision – to help lift living standards in the valleys and enable Cardiff to keep growing by revamping the aged and long‑neglected rail lines connecting the city to its hinterland.

A rare opportunity

The programme involves fully electrifying the 170km of the Core Valley Lines, laying 180km of new track – much of it to convert old single‑track routes to double‑track – upgrading the 52 existing stations and building two brand‑new ones. A £100m depot and signalling control centre has also been constructed at Taff’s Well, six miles north of Cardiff – a place historically regarded as the gateway to the valleys.

Two fleets of new hybrid battery/electric trains complete the picture, ultimately resulting in much faster, more frequent and more direct trains, to provide what has been described as a ‘tube‑like’ service in and out of the capital.

Black swans come visiting

Karl Gilmore, Director of Rail Infrastructure at TfW, describes it as a “once in a generation” opportunity, but also admits that substantial external black swan challenges have had to be overcome, including COVID‑19, which took off just at the vital but sensitive point when responsibility for the Core Valley Lines assets was due to be transferred from Network Rail to the Welsh government so that the groundworks could start.

“We were so close to it not coming over because of COVID – the trigger [for the assets transfer] was late February into March 2020, just when COVID hit,” recalls Gilmore. The transfer went ahead eventually, some eight months late, but the project structure that emerged was highly resilient and agile, he says, at least partly because of all the challenges faced.

“One thing we recognised right from the start is that no single contractor in the world could deliver what we needed, because it’s so multifaceted – there’s signalling, telecoms, permanent way, electrification. We knew we had to divide all the work packages up.”

And so, with TfW acting as client, several delivery partners were chosen – Balfour Beatty, Amey Infrastructure Wales, Alun Griffiths and Siemens Rail. As a new and relatively small organisation working with such major industry players, TfW devised an innovative collaborative alliance called the Craidd Alliance (craidd being the Welsh word for ‘core’) to unite them all on a level playing field.

A high-vis approach

The project’s leaders made sure to get out into the field to communicate their vision to the front‑line teams and other stakeholders, measuring ‘visible felt leadership’.

“This is the time spent physically pressing the flesh, getting out there and being curious,” Gilmore says. Because there is a world of difference between being told that this is the right way to do something and actually seeing your leaders exhibit that behaviour in person.

It made a real impact on team cohesion within the alliance, says Georgia Cope, Assistant Project Manager for TfW, who worked on installing the thousands of concrete piles and steel gantries required for electrification.

“I always knew exactly who each director was – they were familiar faces who you could have a conversation with or ask for a bit of advice. From the people working on site up to the senior leaders, we all knew what the challenges were and were brought along together as a team.”

Innovative technologies as well as processes were also employed, including digital twin computer models of the Core Valley Lines assets, created using aerial drone surveys. Modernising the signalling, electrifying the line and constructing several new twin‑track sections required a nine‑month closure, but, in February 2024, the line reopened, initially running two trains an hour, but with the capacity for four an hour – a fourfold increase in frequency.

Smart electrification

The single most significant enabling technology, says Gilmore, is the mode of electrification used. Called variously ‘smart’ or ‘discontinuous’ electrification, it was devised by TfW and Amey and neatly sidesteps one of the biggest issues that faced the project – the fact that there simply isn’t sufficient clearance to fit modern overhead powerlines to much of the Victorian rail infrastructure in the valleys. Bridges and tunnels in particular lack sufficient headroom, and the conventional solutions – either raising the structure or lowering the track bed – would have been both too slow and too expensive.

By using hybrid trains that can run on battery power for a short time, discontinuous electrification allows the Core Valley Lines to be electrified quickly and at much lower cost. When a train comes to a tunnel or a low bridge, sensors trigger the retraction of its overhead pantograph and it passes through on battery power before flipping the pantograph back up and switching to overhead power again on the other side.

The Core Valley Lines programme represents the single largest application of discontinuous electrification in the UK, says Gilmore, and without it the scope of the project would probably have been seriously curtailed.

“It’s brilliant technology; we’ve saved the best part of £100m by not having to rebuild bridges,” he says. The use of modular buildings, solar power on site and recycled concrete wherever possible has also helped to limit the carbon footprint of the works. In particular, the use of circular hollow section piling, rather than conventional concrete pads, has saved an estimated 2.2 million tonnes of carbon emissions.

Staying on track

The programme’s blend of people, process and technology has enabled it to stay on track despite serious setbacks along the way, and it is “82.5% complete” as of October 2024, says Gilmore, with passengers already enjoying the benefits of new trains and faster services on three of the lines, with the remaining works due for completion by the end of the year.