South Wales 'Metro' updates

[5021]

Despite announcements that the Cardiff Bay - Pontypridd services were due to be suspended from 22nd March, they do seem to be running after all, presumably because the electrification delay on the Bay line means they can't run any 398s.

Yas, according to Realtime Trains, from yesterday (29th March) the service has reverted to what it was until 21st March i.e. 2 per hour to Pontypridd and 2 per hour to Queen Street Mon - Sat and 1 per hour to Ponty and 3 to Queen Street on Sundays. 398 test runs from Taffs Well Depot ARE taking place but not many - one to Treherbert and back on 23rd, a round trip each to Aberdare and Treherbert on 26th, 27th and today, 30th. That's against paths for 4 round trips to both destinations 7 days a week and a fifth to Treherbert on Saturdays! Presumably for whatever reason and very disappointingly there's no immediate prospect of this spare capacity being used and it's come to the attention of service planners?

 

[AdamWW]

Yas, according to Realtime Trains, from yesterday (29th March) the service has reverted to what it was until 21st March i.e. 2 per hour to Pontypridd and 2 per hour to Queen Street Mon - Sat and 1 per hour to Ponty and 3 to Queen Street on Sundays. 398 test runs from Taffs Well Depot ARE taking place but not many - one to Treherbert and back on 23rd, a round trip each to Aberdare and Treherbert on 26th, 27th and today, 30th. That's against paths for 4 round trips to both destinations 7 days a week and a fifth to Treherbert on Saturdays! Presumably for whatever reason there's no immediate prospect of this spare capacity being used and it's come to the attention of service planners?

OK that's very good then.

 

[EveningStarr]

Could it be that they've done this in anticipation of the first 398 entering service and unable to be rescued? If there's only one and it breaks down on a Ponty leg, it would cause unending havoc, whereas if it were locked in on the Bay line, it would only affect those passengers and not the rest of the network. Obviously we're a little way off one being in service yet, but does anyone know if that could be the reason? It's very inconsistent too, whether they run a full service of 3 diagrams or just a CDQ>CDB shuttle.

 

[Cardiff123]

Yas, according to Realtime Trains, from yesterday (29th March) the service has reverted to what it was until 21st March i.e. 2 per hour to Pontypridd and 2 per hour to Queen Street Mon - Sat and 1 per hour to Ponty and 3 to Queen Street on Sundays. 398 test runs from Taffs Well Depot ARE taking place but not many - one to Treherbert and back on 23rd, a round trip each to Aberdare and Treherbert on 26th, 27th and today, 30th. That's against paths for 4 round trips to both destinations 7 days a week and a fifth to Treherbert on Saturdays! Presumably for whatever reason there's no immediate prospect of this spare capacity being used and it's come to the attention of service planners?

If, even at this stage, there are still very limited 398 testing & crew training runs happening, it's very concerning. It's almost as if the spin & PR doesn't match the reality......

 

[VR494]

If, even at this stage, there are still very limited 398 testing & crew training runs happening, it's very concerning. It's almost as if the spin & PR doesn't match the reality......

Driver instructors have today only began to learn the traction. The infrastructure down the bay is not finished, and until the OLE works are completed in the next few weeks - it’s not ready.
The ones out on runs are still on proving, and there is a long way to go. If one does come out there will undoubtedly be problems.

 

[positron]

I recall they had the pontypridd to bay services in as last minute cancellations the other day. So it might be that just did the announcement to give them leeway to cancel the service if they want to, but for now they're just choosing to run a service.

I hope for the sake of everyone using the valleys services that the 398s do magically work out and come winter timetable things are far improved. I'm not really sure what a plan B looks like. There's no spare diesel traction and the 150s are nearing end of life. If I were Welsh government I'd definitely be considering legal action if things don't resolve soonish.

 

[Markdvdman]

Well speaking to fellow passengers this am about the return ooff 150s. They are not happy. Understandable this is dying stock. It is dreadful to go back years. There will be many more cancellations for sure.

 

[CapitalStar378]

Maybe if they'd retained the 175s then 197s could have been used on the TAM lines as an interim measure. Benefit of hindsight of course, but most new traction introductions have not gone well in the UK over the last few years.

 

[VR494]

Maybe if they'd retained the 175s then 197s could have been used on the TAM lines as an interim measure. Benefit of hindsight of course, but most new traction introductions have not gone well in the UK over the last few years.

They need to spend some money on the infrastructure, switching between OLE and battery on units that aren’t designed to be worked this is causing havoc with the onboard systems. Various changes in frequency, systems already under load it’s throwing up faults. The beacons are also not functioning the way they are intended either, with both 756 and 398.

 

[CapitalStar378]

They need to spend some money on the infrastructure, switching between OLE and battery on units that aren’t designed to be worked this was is causing havoc with the onboard systems. Various changes in frequency, systems already under load it’s throwing up faults. The beacons are also not functioning the way they are intended either, with both 756 and 398.

Apart from that, all going swimmingly

 

[AdamWW]

Apart from that, all going swimmingly

Well obviously as a passenger it's hard to know what might be going wrong behind the scenes (TfW certainly won't tell us) but at the moment reliability on the Valley Lines seems to be vastly improved compared to how it was not so long ago.

 

[edwin_m]

According to this month's Modern Railways, the extra capacitance of the ground level 25kV feeders increases power consumption significantly, even when no trains are running.

 

[VR494]

Well obviously as a passenger it's hard to know what might be going wrong behind the scenes (TfW certainly won't tell us) but at the moment reliability on the Valley Lines seems to be vastly improved compared to how it was not so long ago.

Lucky the 756’s have a good range on battery and can use the diesel generators to top up, otherwise there be a lot of cancellations. If I had a pound for every time I’ve heard a signaller advise a driver to ban the pantograph and proceed on battery only; it’s a daily occurrence!

== Doublepost prevention - post automatically merged: 31 Mar 2026 ==

https://www.walesonline.co.uk/news/wales-news/south-wales-metro-massively-over-33692966 1.3bn and counting, the 398’s now not due until the summer.

 

[DS25]

https://www.walesonline.co.uk/news/wales-news/south-wales-metro-massively-over-33692966 1.3bn and counting, the 398’s now not due until the summer.

If only TfW just bought a load of 756’s in the first place instead of messing about with 398’s

 

[CapitalStar378]

If only TfW just bought a load of 756’s in the first place instead of messing about with 398’s

I wonder where we'd be if MTR had been chosen over Keolis Amey back in 2018. I think they were suggesting a more extensive tram network for Cardiff, which could have meant trams and heavy rail being purchased for the Metro. But we'll never know.

 

[Caaardiff]

If only TfW just bought a load of 756’s in the first place instead of messing about with 398’s

That would have been the best case for the whole network change. Taffs Well is a restricted Depot, probably not in the best location, but it was a PR winner for TFW at the time as investment in the Valleys.
398's could have still been used on Cardiff Crossrail (if it ever happens) but on a much smaller scale.
Supposedly Barry Depot is also going to become more used in the future, which was never part of the original plans.

A more sensible approach would have been to take on Barry Depot and split the Stadlers between Canton and Barry, take on Landore and move 153 maintenance, along with stable 197's and even Mark4's to free up space on Canton for more Stadlers.
People don't necessarily want a train every 5 mins, every 10-15 mins is more than suitable provided the train is long enough, which the Stadlers are.

 

[AdamWW]

People don't necessarily want a train every 5 mins, every 10-15 mins is more than suitable provided the train is long enough, which the Stadlers are.

But if you provide 15 minute frequencies at the extremities you end up with more frequent services on the common parts of the route (unless somehow you run bits as a shuttle service).

 

[MikePJ]

According to this month's Modern Railways, the extra capacitance of the ground level 25kV feeders increases power consumption significantly, even when no trains are running.

Yeah, I saw that. I think the author is overstating the importance of this issue - if the capacitance issue is considered a big enough deal it can be fixed by installing inductor units nearby. There may even be some already installed. (The author of that article makes it clear that he’s opposed to discontinuous electrification and this is just one more reason not to like it).

 

[AdamWW]

Yeah, I saw that. I think the author is overstating the importance of this issue - if the capacitance issue is considered a big enough deal it can be fixed by installing inductor units nearby. There may even be some already installed. (The author of that article makes it clear that he’s opposed to discontinuous electrification and this is just one more reason not to like it).

Capacitance will alter the power factor but does it cause significant power loss?

 

[edwin_m]

Yeah, I saw that. I think the author is overstating the importance of this issue - if the capacitance issue is considered a big enough deal it can be fixed by installing inductor units nearby. There may even be some already installed. (The author of that article makes it clear that he’s opposed to discontinuous electrification and this is just one more reason not to like it).

Capacitance will alter the power factor but does it cause significant power loss?

I think the issue is that with no trains running, the supply is charging and discharging the capacitance 100 times per second so there is significant current flowing through the resistance of the cables. I'm not convinced adding inductors will help with that, although they may make a difference when trains are running. But I didn't take much in from power engineering lectures, and that was 40 years ago.

Presumably the "extension lead" from Heyrod to Ordsall Lane has the same problem.

 

[RichardAsh1981]

Perhaps not the right thread, but

I'm not convinced adding inductors will help with that, although they may make a difference when trains are running.

The trains don't make any difference. Adding an inductor of just the right size could exactly cancel out the effects of the cable capacitance. You would need one per cable, so the economics generally don't work out. You actually need less inductance than at first glance, because it turns out that the overhead sections add some inductance of their own ...

It is normal to have the reverse problem in industry, too much inductance (induction motors) causes poor power factor, and the solution is to add a capacitor bank!

Extra cable capacitance in the system will also reduce the system impedance at high frequencies, which should make harmonics less of an issue - I don't know if this is significant in practice.

Presumably the "extension lead" from Heyrod to Ordsall Lane has the same problem.

Indeed, otherwise known as "not a lot".

 

[Richard Scott]

Perhaps not the right thread, but

The trains don't make any difference. Adding an inductor of just the right size could exactly cancel out the effects of the cable capacitance. You would need one per cable, so the economics generally don't work out. You actually need less inductance than at first glance, because it turns out that the overhead sections add some inductance of their own ...

It is normal to have the reverse problem in industry, too much inductance (induction motors) causes poor power factor, and the solution is to add a capacitor bank!

You can't cancel capacitance or inductance out completely as you can end up with huge voltages across both elements.

 

[MikePJ]

You can't cancel capacitance or inductance out completely as you can end up with huge voltages across both elements.

It's very commonly done in industry as RichardAsh1981 points out (Hi Richard!) - you don't eliminate it completely but you can reduce the "power factor" - the amount of power being wasted in capacitive or inductive loads - to a more acceptable level, which has the important effect of reducing the electricity bill from the grid. To reiterate what I said earlier about the Modern Railways article: any competent power engineer would have pointed out the capacitive loading issue and were it economical to correct for it then this would likely have been done. Discontinuous electrification is about reducing initial capital cost and the quid-pro-quo is an increase in running costs (more wear on circuit breakers and pantographs, greater operational complexity, and also this issue with capacitive loading). The author of the article makes it clear that he is very against discontinuous, and so I think his article is rather biased - he presents this as a "slam dunk" on why discontinous is a bad idea. I am sympathetic to his argument - Garry Keenor (well-known electrification engineer and author) has also made good arguments about why discontinuous is not a good solution for main lines - but I don't think this was a very good article taking a balanced view, it's more of a rant.

 

[5021]

Driver instructors have today only began to learn the traction. The infrastructure down the bay is not finished, and until the OLE works are completed in the next few weeks - it’s not ready.
The ones out on runs are still on proving, and there is a long way to go. If one does come out there will undoubtedly be problems.

It seems that the OLE on the Bay branch's existing single track (so therefore NOT complete despite TfW's claim?) must be OK. RTT shows an ECS working from Taffs Well Depot to the Bay in the very early hours of this morning followed by 5 round trips from there to Radyr and back via (of course) Llandaf, well within schedule in the end. The final return from the Bay to the Depot is shown as cancelled, but that can't be true as the normal service began on time. There are paths for this to be repeated the next 2 mornings (Fri 3rd and Sat 4th April) but none beyond that as yet, though the Treherbert and Aberdare paths continue. There was also a trip from TW depot to Aberdare this morning which was also wihin schedule but the folowing one to Treherbert was cancelled though the afternoon path was used .

 

[Cardiff4]

TfW have now officially announced that Ty Glas station will reopen next Saturday (4th April) .

 

[AdamWW]

It seems that the OLE on the Bay branch's existing single track (so therefore NOT complete despite TfW's claim?) must be OK. RTT shows an ECS working from Taffs Well Depot to the Bay in the very early hours of this morning followed by 5 round trips from there to Radyr and back via (of course) Llandaf, well within schedule in the end.

Unless it has enough battery to do the Bay on a limited number of workings like that without overhead power?
Not necessarily the same as being able to do it all day.

 

[positron]

Yeah presumably if it can do gabalfa to past ninian park with battery it can probably do gabalfa to the bay and back again with battery?

 

[5021]

It seems that the OLE on the Bay branch's existing single track (so therefore NOT complete despite TfW's claim?) must be OK. RTT shows an ECS working from Taffs Well Depot to the Bay in the very early hours of this morning followed by 5 round trips from there to Radyr and back via (of course) Llandaf, well within schedule in the end. The final return from the Bay to the Depot is shown as cancelled, but that can't be true as the normal service began on time. There are paths for this to be repeated the next 2 mornings (Fri 3rd and Sat 4th April) but none beyond that as yet, though the Treherbert and Aberdare paths continue. There was also a trip from TW depot to Aberdare this morning which was also wihin schedule but the folowing one to Treherbert was cancelled.

Yeah presumably if it can do gabalfa to past ninian park with battery it can probably do gabalfa to the bay and back again with battery?

Probably so, but then it makes you wonder about the purpose and value of these nocturnal trials if only battery is used on the Bay line!

 

[VR494]

Probably so, but then it makes you wonder about the purpose and value of these nocturnal trials if only battery is used on the Bay line!

Safety notices in the WON state that the work planned for the 22nd switch on did not go ahead as advertised.

There's currently an issue with the lathe as well in Canton, any trains needing flats treated will need to be taken up North, and I have no doubt a fuel shortage maybe coming too (another issue).

When these things do come into service, there will be endless issues, engineers, managers and staff have already stated it, the whole system is flawed - but the Welsh Government want to tix that big box!

 

[5021]

Safety notices in the WON state that the work planned for the 22nd switch on did not go ahead as advertised.

There's currently an issue with the lathe as well in Canton, any trains needing flats treated will need to be taken up North, and I have no doubt a fuel shortage maybe coming too (another issue).

When these things do come into service, there will be endless issues, engineers, managers and staff have already stated it, the whole system is flawed - but the Welsh Government want to tix that big box!

Thanks, and yes a 231 was dragged to Holyhead by a 37 on March 16th because of the Canton lathe problem. Crewe's was (and still is?) out of action as well whereas Holyhead's was new just in time for leaf fall last autumn.