South Wales Metro - Future

[MikePJ]

Given the timescales being talked about - and that this is a vision rather than a definite funded programme - I would assume that the short term solution would be to add electrification to Cogan to enable 398s to Penarth and reduce diesel burn on the existing 756 fleet, but once the (much more complex) project to electrify to Bridgend or beyond is in place the 756s could be replaced on the Rhymney/VoG services with a battery/overhead FLIRT variant, allowing the tri-mode 756s to be used somewhere else where their diesel engines are of value.

 

[anthony263]

Given the timescales being talked about - and that this is a vision rather than a definite funded programme - I would assume that the short term solution would be to add electrification to Cogan to enable 398s to Penarth and reduce diesel burn on the existing 756 fleet, but once the (much more complex) project to electrify to Bridgend or beyond is in place the 756s could be replaced on the Rhymney/VoG services with a battery/overhead FLIRT variant, allowing the tri-mode 756s to be used somewhere else where their diesel engines are of value.

One part of the document mentions electrification of the mainline between Cardiff and Bridgend if that's the case id wire platform 1a up and platform 3 too the latter for the unit which does the Maesteg shuttle service to recharge between trips

 

[D.L.P.R.]

I can see that a Maesteg shuttle is on the TfW 'wishlist'. Would this require a passing loop to be built north of Tondu or would it be possible to run a shuttle to Bridgend alternating with the existing Maesteg-Cardiff service without one, or are they proposing a 2tph shuttle with all passengers needing to change at Bridgend? If an alternating service, what would the likely timetable be to fit in between the Cardiff service? Sorry for all the questions!

 

[John R]

I can see that a Maesteg shuttle is on the TfW 'wishlist'. Would this require a passing loop to be built north of Tondu or would it be possible to run a shuttle to Bridgend alternating with the existing Maesteg-Cardiff service without one, or are they proposing a 2tph shuttle with all passengers needing to change at Bridgend? If an alternating service, what would the likely timetable be to fit in between the Cardiff service? Sorry for all the questions!

Yes, you would need a passing loop. It would probably be around Tondu, and the very antiquated ramshackle layout there rationalised at the same time with the semaphores and box swept away.

 

[SWML9102]

Yes, you would need a passing loop. It would probably be around Tondu, and the very antiquated ramshackle layout there rationalised at the same time with the semaphores and box swept away.

A passing loop would be needed, but ideally North of Tondu, in the vicinity of the paper mills, to enable 30 minute frequency. What is also needed is a double lead (is that the correct term?) at the bottom of the branch to allow northbound trains to clear the mainline if there is a late running south bound trains and avoid the Swansea bound platform at Bridgend being blocked.

 

[anthony263]

A passing loop would be needed, but ideally North of Tondu, in the vicinity of the paper mills, to enable 30 minute frequency. What is also needed is a double lead (is that the correct term?) at the bottom of the branch to allow northbound trains to clear the mainline if there is a late running south bound trains and avoid the Swansea bound platform at Bridgend being blocked.

Sure there used to be double track on the branch between wildmill and Sarn.

 

[Caaardiff]

Isn't there already a loop at Tondu? It's just no longer in use.

 

[anthony263]

Isn't there already a loop at Tondu? It's just no longer in use.

Needs resignalling for use by passenger services and the track relade. Also requires the garw loop connection be severed and lifted although the .Margam line is going to.remain.

That line needs some use a waste seeing it just sitting there with the.weeds growing

 

[Cardiff123]

TfW's newly-published vision document says that the plan is for "part-electrification" between Cardiff and Cogan to enable tram-trains to reach Penarth and also has the enigmatic comment that "when combined with electrification of the South Wales Main Line, this will allow battery trains to run on the Vale of Glamorgan line". I presume that what this means is that once there are wires at Bridgend for the main line, the bay platform for the VoG will also be wired, and so the 756s will be able to top up their batteries during turnaround and eliminating the need for running on diesel.

https://tfw.wales/sites/default/files/2026-02/TTT-Final_ENG.pdf

It seems to me that TfW's ambitions are permanently hamstrung by the fact that NR owns the infrastructure and TfW / Welsh Government must take a begging bowl to the DfT and ultimately the UK Treasury to get schemes funded and approved.

Eg. Why not electrify the entire line from Cardiff to Barry & Barry Island? The only obstacle along the line is Cogan tunnel, the wires could stop at Cogan Station and start again after the tunnel. There's very few (if any?) low bridges to deal with along the line. Yet no doubt for the sake of getting *possible* UK Treasury approval, Cardiff to Cogan junction, not even to Penarth, is all TfW can justify.

 

[MarkyT]

It seems to me that TfW's ambitions are permanently hamstrung by the fact that NR owns the infrastructure and TfW / Welsh Government must take a begging bowl to the DfT and ultimately the UK Treasury to get schemes funded and approved.

Eg. Why not electrify the entire line from Cardiff to Barry & Barry Island? The only obstacle along the line is Cogan tunnel, the wires could stop at Cogan Station and start again after the tunnel. There's very few (if any?) low bridges to deal with along the line. Yet no doubt for the sake of getting *possible* UK Treasury approval, Cardiff to Cogan junction, not even to Penarth, is all TfW think they can justify.

With batteries, any additional wiring is beneficial for extending range and resiliency. The concept doesn't prevent any further incremental extensions in the future, if expedient. Most beneficial would be from Cogan through the CVL platforms at Central and up the spur to Queen Street. As the busiest parts of the network, station dwells here are lengthy, making them a great place to take on a big charge while stationary.

 

[MikePJ]

It seems to me that TfW's ambitions are permanently hamstrung by the fact that NR owns the infrastructure and TfW / Welsh Government must take a begging bowl to the DfT and ultimately the UK Treasury to get schemes funded and approved.

Eg. Why not electrify the entire line from Cardiff to Barry & Barry Island? The only obstacle along the line is Cogan tunnel, the wires could stop at Cogan Station and start again after the tunnel. There's very few (if any?) low bridges to deal with along the line. Yet no doubt for the sake of getting *possible* UK Treasury approval, Cardiff to Cogan junction, not even to Penarth, is all TfW think they can justify.

To be fair, TfW is also trying to be efficient with its investment money. Providing partial electrification between Canton ( where there’s already a feeder station) and Cogan is relatively cheap.

 

[Topological]

A passing loop would be needed, but ideally North of Tondu, in the vicinity of the paper mills, to enable 30 minute frequency. What is also needed is a double lead (is that the correct term?) at the bottom of the branch to allow northbound trains to clear the mainline if there is a late running south bound trains and avoid the Swansea bound platform at Bridgend being blocked.

Even if it was not a double lead junction, adding a loop immediately before the main line would allow trains to clear the main line. I assume that would be cheaper and the land is there.

It would be interesting to see what could be done with an hourly Cardiff - Maesteg and a hourly shuttle from Bridgend-Maesteg.

 

[MarkyT]

Even if it was not a double lead junction, adding a loop immediately before the main line would allow trains to clear the main line. I assume that would be cheaper and the land is there.

It would be interesting to see what could be done with an hourly Cardiff - Maesteg and a hourly shuttle from Bridgend-Maesteg.

Either way, you'd want the double track to finish before Wildmill station, to avoid the need for a second platform and access arrangements. A double junction could be beneficial here if trains regularly cross, as the movements to and from the branch can take place simultaneously, clearing the mainline platforms more quickly for other traffic.

Here's my animation of such a layout. Note the branch trains don't make good connections with the mainline expresses. Because they also perform the mainline stopping service role, Cardiff-bound Maesteg local trains need to leave around ~15 minutes before a fast to avoid the express catching up. That probably helps discourage Cardiff passengers from the branch changing onto the expresses.

 

[anthony263]

Even if it was not a double lead junction, adding a loop immediately before the main line would allow trains to clear the main line. I assume that would be cheaper and the land is there.

It would be interesting to see what could be done with an hourly Cardiff - Maesteg and a hourly shuttle from Bridgend-Maesteg.

Based on the current timings an hourly shuttle could pass the Cardiff trains using the existing loop at Tondu.

I do think the layout should be retained especially if we see electrification extended west of Cardiff the Margam branch could provide a good diversionary route

 

[Smwrff]

Assuming that TAM sevices will in future have 3x2tph to Cardiff Bay and 3x2tph to Cardiff Central (with some services looping around City Line)....

What should happen to Coryton and Penarth services? The latest TfW plan includes a Station connection to Crossrail, and electrification to Cogan....

Which opens up the possibility of Coryton to Penarth services using 398s; and Coryton to Bay, and Penarth to Bay. These could each be 2tph - so giving 4tph at Penarth & Coryton, and 8 tph at Bay. This would release a few 856s to use elsewhere.

Or is a City Line to Coryton service a better option?

 

[MikePJ]

Based on this diagram, which is one of Mark Barry’s but seems to turn up in a lot of official documents, the Penarth branch will have 2tph to Coryton and 2tph to Cardiff Bay.

There’ll then be a 2tph Caerphilly-Cardiff Bay service as well. The extra 2tph on Coryton would then serve the City Line to Radyr, bringing back the direct service that was previously used by a lot of schoolchildren.


https://www.railforums.co.uk/attachments/1770300752958-png.197483/

== Doublepost prevention - post automatically merged: 22 Feb 2026 ==

Penarth branch can’t handle more than 4tph without doubling the track, which at one point was in the plan but hasn’t been mentioned since. There is going to be an extra arrival platform at Penarth but that’s mostly to help with recovering from disruption.

 

[Smwrff]

Can 398s use Caerphilly tunnel?

 

[anthony263]

Can 398s use Caerphilly tunnel?

I dont think.so at the moment although I think tbey might be able to if the wires were extended closer to the tunnel on the Cardiff side

 

[Envoy]

I dont think.so at the moment although I think tbey might be able to if the wires were extended closer to the tunnel on the Cardiff side

The wires end just south of Lisvane station - presumably so they would not have to do any work to replace the footbridge? (Those with impaired mobility must go around via the road bridge).

 

[MarkyT]

Based on the current timings an hourly shuttle could pass the Cardiff trains using the existing loop at Tondu.

I do think the layout should be retained especially if we see electrification extended west of Cardiff the Margam branch could provide a good diversionary route

Ideally you'd need a new curve at Tondu so trains could run direct without reversal.

Here I've squeezed a tight 150m radius curve in:


Layout modification with additional platform to provide a Penryn arrangement. Removal of the W-N connection allows a level pedestrian connection between them and street egress.

 

[anthony263]

Ideally you'd need a new curve at Tondu so trains could run direct without reversal.

Here I've squeezed a tight 150m radius curve in:
View attachment 198745

Layout modification with additional platform to provide a Penryn arrangement. Removal of the W-N connection allows a level pedestrian connection between them and street egress.

View attachment 198746

A curve would be quite difficult especially with all the development

 

[MarkyT]

A curve would be quite difficult especially with all the development

The Ogwr or Tondu Enterprise Centre is the main obstacle, looking at Streetview. Formerly an NCB training centre, it has 29 office and 24 workshop units that might be relocated. I don't think there's anything historic from previous uses there today. Abandonment of the west to north rail connection might release some new space for replacement buildings for affected businesses. Some of the existing units might remain, with a new access created from Brynn Rd.

Tondu - Business In Focus

Tondu Enterprise Centre comprises 29 offices and 24 industrial workshops on the site of the old National Coal Board Training Centre.

www.businessinfocus.co.uk

 

[Topological]

What is the new curve offering though?

I can see the redevelopment of Tondu station, but the curve is purely to make it possible to use a line that has no use?

Even if you go to the trouble of bypassing Pyle for diversions, the line still needs to close if anything between Pyle and Britton Ferry is out of action.

It is much easier to just use rail replacement buses.

 

[Peter Sarf]

What is the new curve offering though?

I can see the redevelopment of Tondu station, but the curve is purely to make it possible to use a line that has no use?

Even if you go to the trouble of bypassing Pyle for diversions, the line still needs to close if anything between Pyle and Britton Ferry is out of action.

It is much easier to just use rail replacement buses.

As a passenger I prefer a train on a slower detour rather than a bus.

 

[Topological]

As a passenger I prefer a train on a slower detour rather than a bus.

To the point of being willing to fund such a piece of track?

Although people may "prefer" this only buys you a diversion for a section between Pyle and Bridgend that is basically plain line. How often will that close?

I do not begrudge anyone who wants to pay more and have diversion lines, but I suspect most people prefer not to use money on projects like a diversion for Pyle to Bridgend.

 

[MarkyT]

What is the new curve offering though?

I can see the redevelopment of Tondu station, but the curve is purely to make it possible to use a line that has no use?

Even if you go to the trouble of bypassing Pyle for diversions, the line still needs to close if anything between Pyle and Britton Ferry is out of action.

It is much easier to just use rail replacement buses.

I don't see it primarily for diversions, more as an additional bidirectional relief line, mainly for freight, which can thus be passed by better performing passenger trains. It might justify a bit more double track on the branch between Tondu and Bridgend, likely starting on the Bridgend side of the M4 bridge.

 

[Topological]

I don't see it primarily for diversions, more as an additional bidirectional relief line, mainly for freight, which can thus be passed by better performing passenger trains. It might justify a bit more double track on the branch between Tondu and Bridgend, likely starting on the Bridgend side of the M4 bridge.

I appreciate that there will be more trains going in and out of Port Talbot once the arc furnaces come online, but it is still a very expensive project for something that could be achieved with a bit of loop lengthening here and there.

The only advantage remains that there is a way of getting around an obstacle between Bridgend and Pyle.

If we were talking about a world in which Swansea - Maesteg services made sense then that might be different. However, the direct bus never came back after Covid. Then, any Swansea train would need the northern curve and the northern curve is proposed for removal as part of building the south curve.

 

[Tomos y Tanc]

If we were talking about a world in which Swansea - Maesteg services made sense then that might be different. However, the direct bus never came back after Covid.

It's all a bit chicken and egg really.

Historically, Maesteg probably did look more to Swansea than Cardiff as its regional centre but those days are long gone. With very little employment left in the Llynfi valley itself, most work opportunities are in the Bridgend area and in terms of shopping, entertainment etc, people are more likely to head east rather than west.

The question is has that situation arisen because of poor transport links or do the poor services reflect a lack of demand. I suspect the latter to be the case and that a 'build it and they will come' approach is likely to fail.

 

[SWML9102]

It's all a bit chicken and egg really.

Historically, Maesteg probably did look more to Swansea than Cardiff as its regional centre but those days are long gone. With very little employment left in the Llynfi valley itself, most work opportunities are in the Bridgend area and in terms of shopping, entertainment etc, people are more likely to head east rather than west.

The question is has that situation arisen because of poor transport links or do the poor services reflect a lack of demand. I suspect the latter to be the case and that a 'build it and they will come' approach is likely to fail.

If any future Maesteg - Swansea was viable it would be better to go via Bridgend and reverse there anyway,

 

[Caaardiff]

If any future Maesteg - Swansea was viable it would be better to go via Bridgend and reverse there anyway,

An hourly Maesteg to Swansea via Bridgend could also increase swanline stops to hourly if pathing allowed. It would mean the option to change at Bridgend for anyone travelling on to Cardiff, complimenting the current Maesteg to Cardiff.