Cardiff West Junction…

I cover many of the issues raised below and wider schemes Wales, in my book
“How to build a Metro“

This is a copy of an email I sent to UK and WG Ministers in July 2024 on the subject of “Cardiff West Junction” – a piece of essential rail infrastructure in Cardiff which has fallen through the cracks. The situation for me exemplifies the constitutional failings of the current rail industry ecosystem which continues to “fail” Wales.

PS In its June 2025 Comprehensive Spending Review, the UK Government committed to address this issues and fund further enhancement work at Cardiff West. I like to think my efforts were a contributory factor in that decision.

FAO:
Rt Hon Louise Haigh MP, Secretary of State for Transport
Lord Hendy of Richmond Hill CBE, Minister of State (Rail Minister)
Ken Skates MS, Cabinet Secretary for the Economy, Transport and North Wales
Jo Stevens MP, Secretary of State for Wales
CC Huw Thomas, Leader of Cardiff Council

Ministers

Can I bring to your attention what I and many others involved in rail/metro in the Cardiff Capital Region, view as an urgent issue.  That being the need to secure DfT/UK Gov development and capital enhancement funding for the “Cardiff West junction” tactical project and for this work to be combined with Network Rail’s Renewal work already planned for “Cardiff West Junction” early in 2028.

This enhancement will address a long-standing network bottleneck on the core valley lines which currently restricts services on the city line in the west of Cardiff to just 2tph.  Without action a large populous part of Cardiff (see figure below re city and Coryton lines)  will be denied “turn up and go” metro services that will be available nearly everywhere else on the Metro network and leaves a big “Metro hole” in Cardiff itself. (and it is a well know transport planning rule that few people wait 30 mins for a 15 min trip!) 

Academic data also demonstrates that elasticities of demand for increasing rail service frequency from 2tph to 4tph are more often greater than one in urban areas with sufficient catchment  population as is the case in Cardiff (this is not always captured in rail planning and transport modelling which sometimes use an average elasticity figure)

This enhancement is also a critical path intervention that will enable further work to optimise/simplify planned CVL metro services,  deliver/operate 4tph on the City Line and Coryton line and enable the “Station link” to connect Crossrail Phase 1a to the west and the city line at Cardiff Central.

This is extremely frustrating as this issue has been known about for at least 15 years (noted in many earlier NR route studies and I set out the issues in my 2013 Metro Impact Study for Welsh Government!). In fact, an enhancement was originally included within the scope of NRs Cardiff Area Signalling and Renewal (CASR) project in 2014/5.   However, the requirement to enable 4tph on the City line was “value engineered” out of scope by DfT/NR which in effect has handed an operational liability to TfW and CVL Metro services.  

For me this exemplifies the constitutional failing of the current rail ecosystem where Wales  has little no say over DfT “England and Wales” enhancement funding, and where a scheme like Cardiff West,  despite the best efforts of some officials, is just too “inconsequential” when viewed from Marsham street.  Had rail been devolved this would have been done years ago.  Now we have a piece of NR kit whose primary function is to support TfW’s CVL Metro services which are constrained without the enhancement.

To restate, this is a relatively modest enhancement of the track west of Cardiff Central (this is on NR managed track near the Canton depot) that will allow TfW to operate 4tph on the City Line in the west of the city at a cost I estimate of perhaps £30M.  NR completed initial feasibility and set out two options in 2022.

There is also a clear opportunity now, to make best use of public funds as NR already have plans in place for a renewal programme at Cardiff West in 2028.   It will be far more cost effective if additional funds can be found so that the enhancement to enable 4tph on the city line can be incorporated into the same programme and delivered at the same time and at a lower cost (vs a more costly and disruptive further programme a few years later).

There is funded scheme development work (tbc via NR) planned on Cardiff West this FY, however there is no formal commitment yet to progress from DfT/NR  (which needs I believe £300—400k development funding now to match the funding put forward by WG and CCC) or any capital allocation.

This intervention is the critical path item for all the other metro rail schemes the city has set out (CVL service pattern simplifiation/optimisation, Station link, Coryton 4tph, new CVL Metro stations in Cardiff, etc – this is in effect “Cardiff Crossrail Phase 2”)  and needs UK Gov funding/commitment via the DfT and NR to progress ASAP. 

If approval/funding is not secured in the next few weeks, it is likely that the opportunity to combine the enhancement with the renewal work will be lost.    This for me would be an institutional and constitutional failing that we have to avoid (A subject I know you will be aware that I have written about and published formally and informally over the last few years).  Given the new DfT Ministerial team has enormous knowledge and appreciation of rail issues in Wales I feel confident this can be addressed.

With this Cardiff West critical path measure addressed, plus delivery of some of the other schemes to improve Metro in Cardiff (esp the Crossrail Phase 2– and its vitally important Station link) there is no reason why the CVL cannot exceed the 30M PAX that is the case today on the Tyne and Wear Metro and so deliver major mode shift and decarbonisation benefits.   They both have broadly similar 800M station population catchments; but CVL today is about 10~12M PAX .  The additional CVL network capacity and flexibility will also likely improve vehicle utilisation and reduce subsidy per passenger and provide greater operational flexibility and redundancy.  The wider economic benefits for Cardiff West and the other Cardiff Metro schemes (as part of Cardiff Crossrail Phase 2), are also likely to be significant and will exceed those already set out in the Cardiff Crossrail Phase 1 Business Case.

Best Regards

Mark

This is a small example of how Wales’s rail issues get overlooked in Whitehall. The vital and long standing Cardiff West tactical scheme (which is perhaps a £30M project) pails into insignificance when compared to the existing Uk Gov rail capital programme in play by the DfT (which pretty much ignores Wales).

In stark contrast, we have just seen UK Gov/DfT commit at least £5Bn needed for the necessary extension of HS2 to Euston from Old Oak Common; the proposals for Cardiff Crossrail Phase 2 – esp Cardiff West should be viewed in the same way (albeit a lot less capital is required!) to enhance the value of the CVL Metro upgrade and Cardiff Crossrail Phase 1 investment

There are also many other enhancement schemes needed in Wales – in fact for the NW corridor scheme in Cardiff/RCT, we will need further work at Cardiff west and probably grade separation. But for now, the tactical work is the urgent issue and so my focus is on getting the DfT/UK Gov to find the ££ to get this initial tactical work done alongside the planned renewals in 2028.