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Transport for Wales Class 231 / 756 Stadler FLIRTs

Peter Sarf

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They should have been a bimode like the 755s from the start - it is a very odd decision
Given the 231s are on the face of it just a 755 minus the pantograph and transformer etc I doubt it is much of a big deal to fit a pantograph etc later. It is I hope not going to be a conversion requiring designing and alteration.
 
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Western 52

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Given the 231s are on the face of it just a 755 minus the pantograph and transformer etc I doubt it is much of a big deal to fit a pantograph etc later. It is I hope not going to be a conversion requiring designing and alteration.
Will they need to remove an engine to make space for new equipment I wonder?
 

AdamWW

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Will they need to remove an engine to make space for new equipment I wonder?

Wouldn't have thought so given that the 4 car class 755 bi-modes have 4 engines of (at least according to Wikipedia) are the same type.
 

Peter Sarf

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There is probably even a concrete block on the 231 where the transformer would and could go just to make the weight distribution right.
 

Anonymous10

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It's in Modern Railways. Not that surprised - I did think ordering a DMU only version was saving pennies (given that it's a DEMU anyway) and taking a big hit on flexibility.
Also means the cardiff- Severn tunnel on the Gloucester services can be electric operated possibly? Unsure if it affects Ebbw Vale services.
 

tfw756rider

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https://www.modernrailways.com/article/class-231-hybrid-conversion-under-consideration

Class 231 hybrid conversion under consideration
(Modern Railways, 20/1/25)

Transport for Wales Rail has drawn up plans to progress with converting the 11 four-car Class 231 Stadler FLIRT DEMUs to bi-modes. It has not yet committed to the work, but in October its board was presented with a proposal to mobilise a project team to support the conversion with Stadler.

The 11 Class 231s are operating on the Rhymney line pending electrification, when they will be replaced by Class 756 tri-modes. The Class 231s will then operate services from Cardiff to Maesteg and Cheltenham. They will also supplement Class 197s on the Ebbw Vale line and Class 756s on the Vale of Glamorgan line to Bridgend via Barry.

TfW has a Hybrid Variation Agreement with Stadler that entitles it to serve a Hybrid Conversion Activation Notice on the trains’ manufacturer and owner. TfW has until the end of April 2026 to make a decision. If it does serve the notice, conversion would take up to four years to complete. One unit at a time would undergo conversion.

Without further electrification, the bi-modes would use their pantographs from Cardiff Central to Severn Tunnel Junction or to Ebbw Junction, where Ebbw Vale trains leave the main line. Another possible use for the bi-modes is on TfW’s proposed half-hourly service between Cardiff Central and Bristol Temple Meads, calling at a series of planned new stations on the main line and using the Severn Tunnel’s 25kV supply.

TfW will need to renew the Class 231 leases in 2033 or hand them back. The latter would involve the additional cost of procuring replacements, which would need to be at least bi-mode for continued use after 2040, TfW told Modern Railways.

Staff would then need to be trained on another fleet, and facilities would need changes to accommodate the trains.

Class 231 conversion, rather than new procurement, would avoid increased maintenance costs, with no additional spares, staff or training required, said TfW. Savings would also accrue from reduced Class 231 engine hours, overhaul and diesel costs. Emissions would also reduce. (Rhodri Clark).

https://tfw.wales/sites/default/files/2023-10/Response 51_23 (Final) - Details of Board minutes.docx

Freedom of Information Request 51/23 (Partial Response) (excerpt)
(Transport for Wales, 25/4/23)

Question 2: Details on the planned modifications to the class 231s to make them hybrids as discussed in the board minutes 9/12/22 section 13 and any further updates

Question 2 Response: TfW has entered into a Stadler Class 231 ‘Hybridisation Works Contract’, which provides TfW the option to implement the associated Hybrid Conversion Programme. The programme would see the conversion of the 11 Class 231 Stadler Flirt from diesel only to Bimode trains (pantograph conversion) and is to satisfy part of the terms of the Strategic Partnership Agreement (SPA) with both Stadler and the owners. The timetable for the programme is yet to be determined.

https://tfw.wales/sites/default/files/2023-10/Response 88_23 231 hybrid modification.docx

Freedom of Information Request 88/23
(Transport for Wales, 22/6/23)

Question 1: Could you let me know please what the Class 231 hybrid modification programme involves, and whether it has now been agreed/authorised?

Question 1 Response: The hybrid modification involves the fitting of a pantograph each of the 11 Class 231 Units. All that has been negotiated and authorised to date is an option to activate the Hybrid conversion programme at any trime before 30 April 2026.


Question 2: Would the 231s receive pantographs for use under the OLE between Cardiff and Severn Tunnel Junction, or would they receive batteries, or both?

Question 2 Response: Just pantographs in addition to the current specification. The fitting of a pantograph will provide greater operational flexibility in terms of routes that on which the 231 fleet can operate.


Question 3: Also, what is the timescale of the modification programme? Will the units be modified after they leave the Rhymney line or before?

Question 3 Response: The Hybrid conversion programme option can be activated at any time before 30 April 2026.

== Doublepost prevention - post automatically merged: ==

I wonder if the hybrid / pantograph-fitted 231s would be reclassified (as Class 754, Class 755/5 or Class 757)?
 

AdamWW

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Interesting about running them on the Vale of Glamorgan. At the moment that would also mean running up to Rhymney but maybe there's a plan for additional Vale of Glamorgan services that terminate at Cardiff?

I wonder if the hybrid / pantograph-fitted 231s would be reclassified (as Class 754, Class 755/5 or Class 757)?

Good question. There doesn't seem to be an awful lot of consistency in such things so I could quite imagine them staying as 231s. But I don't think it's easy to predict what whoever makes these decisions would decide.

And I presume the talk about "adding pantographs" is short hand for adding pantographs and transformers, rather than the transformers currently being installed and doing nothing (apart from adding weight).
 

tfw756rider

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Good question. There doesn't seem to be an awful lot of consistency in such things so I could quite imagine them staying as 231s. But I don't think it's easy to predict what whoever makes these decisions would decide.
Surely they'd become 75x as an AC electric-capable FLIRT - I thought that as soon as pantographs (or even transformers, as must have been the case with the pantograph-removed Transport for Wales 769s) are fitted to a unit, it's then an "AC electric unit" as far as looking at it from an electric point of view is concerned. But yes, indeed we can get surprises, so we'll just have to wait and see/hear (etc.)
 

MikePJ

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It's worth noting that the FLIRT design is fundamentally an overhead-powered electric train, and the "power pack" vehicle fitted to the TfW units is only required if you want diesel engines and/or batteries. So the pantograph and transformer will have space reserved for them in one of the passenger-carrying vehicles.

Not wishing to move too much into speculation here, but I suspect Modern Railways' suggestion that these units will be used on new services to Bristol is on the money. That's a service where the units would run under the wires for a significant distance.
 

AdamWW

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Not wishing to move too much into speculation here, but I suspect Modern Railways' suggestion that these units will be used on new services to Bristol is on the money. That's a service where the units would run under the wires for a significant distance.

But in that case...what runs the services the 231s were actually bought for?
 

Western 52

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Just to recap . Is that, and is it still Cheltenham. Ebbw Vale & Maesteg?
If Cardiff to Bristol was an hourly tfw service additional to existing services, only 2 231s would be needed probably. Leaves the rest for the services originally planned for them.
 

CardiffKid

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But in that case...what runs the services the 231s were actually bought for?

Just to recap . Is that, and is it still Cheltenham. Ebbw Vale & Maesteg?

231s are EDMUs with a diesel tank and batteries, no overhead equipment, and were bought for Cheltenham, Ebbw Vale and Maesteg.

Those routes are currently serves by a complete mix (150s, 153s 197s, and very very occasionally still a 158)
 
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MikePJ

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But in that case...what runs the services the 231s were actually bought for?
If they're going to run an additional service to Bristol they're going to need more stock - but I'd argue that the pantograph-equipped 231s make sense for services running primarily along the main line where they can make use of the overhead, and it would make sense to order some extra 197s for other services. (There will doubtless be some political pressure to keep the CAF factory in Newport busy).
 

anthony263

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If Cardiff to Bristol was an hourly tfw service additional to existing services, only 2 231s would be needed probably. Leaves the rest for the services originally planned for them.
Probably for the proposed stopping services to Bristol TM bus journey times would be 65 minutes each way if its serving all of the existing stations plus the proposed new stations between Cardiff and Severn tunnel junction.

I definitely think tfw will be needing extra units. The current fleet of 11 won't be enough for everything so another 5 units at least
 

Rhydgaled

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Given the 231s are on the face of it just a 755 minus the pantograph and transformer etc I doubt it is much of a big deal to fit a pantograph etc later. It is I hope not going to be a conversion requiring designing and alteration.
As well as the traction power differences the class 231s, 755s and 756s each have their own bodyshell differences (number of doors being the obvious one, not sure if there are any other differences).

If Cardiff to Bristol was an hourly tfw service additional to existing services, only 2 231s would be needed probably. Leaves the rest for the services originally planned for them.
The consultation on the new South Wales Main Line stations suggested they are looking at three service options:
  • Option 1
    • 1tph Cardiff Central - Cheltenham Spa
    • 1tph Cardiff Central - Bristol Temple Meads*
  • Option 2
    • 1tph Cardiff Central - Cheltenham Spa
    • 2tph Cardiff Central - Bristol Temple Meads*
  • Option 3
    • 2tph Cardiff Central - Cheltenham Spa
    • 2tph Cardiff Central - Bristol Temple Meads*
* may be operated by GWR rather than TfW - to be decided

Even if GWR end up running the Bristol services and TfW are only running the Cheltenham Spa service there will still be the impact of 5 or 6 additional stations to consider. Would that have a sufficient impact on journey times to require an additional diagram, even if no extra services are operated by TfW?

TfW will need to renew the Class 231 leases in 2033 or hand them back. The latter would involve the additional cost of procuring replacements, which would need to be at least bi-mode for continued use after 2040, TfW told Modern Railways.
Very interesting given that it says 'TfW told Modern Railways' rather than Modern Railways just speculating regarding use after 2040.

If they're going to run an additional service to Bristol they're going to need more stock - but I'd argue that the pantograph-equipped 231s make sense for services running primarily along the main line where they can make use of the overhead, and it would make sense to order some extra 197s for other services. (There will doubtless be some political pressure to keep the CAF factory in Newport busy).
If they really require bi-modes after 2040, then additional class 197s would be insane (I would argue that this applies to the existing fleet also, given that as it is they won't be 35 years old until gone 2050). As for the CAF factory in Newport, perhaps there is something they can do to electrify the class 197s. Alternatively, CAF could build some new battery EMUs for the Core Valley Lines to release tram-trains for the extensions in south-east Cardiff.
 

MikePJ

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If they really require bi-modes after 2040, then additional class 197s would be insane (I would argue that this applies to the existing fleet also, given that as it is they won't be 35 years old until gone 2050). As for the CAF factory in Newport, perhaps there is something they can do to electrify the class 197s. Alternatively, CAF could build some new battery EMUs for the Core Valley Lines to release tram-trains for the extensions in south-east Cardiff.
Yes, I stand corrected - more 197s are a good idea from a fleet uniformity point of view but a bimode or trimode version would be better. CAF are doing a trimode Civity (admittedly as an intercity train) for LNER, so it may not be too hard to do a trimode for TfW, especially if the units don't need the light weight and high Route Avaiability of the 197s.
 

Caaardiff

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More 197s will also come with the extra cost of a new, larger Depot to maintain them.
Only Chester do heavy maintenance of them which is at capacity, and can't see Canton taking that work on.
More Flirts make more sense as they are already maintained at Canton.
TFW should be looking into a direct link from Swansea to Bristol. Cardiff to Bristol is already well served.
 

Rhydgaled

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TFW should be looking into a direct link from Swansea to Bristol. Cardiff to Bristol is already well served.
The additional Bristol services proposed would be all-stations stoppers on the relief lines with five or six new stations. Even with EMUs and the expected relief line linespeed upgrades, these are unlikely to offer an attractive journey time for end-to-end journeys between Cardiff and Bristol. They are probably targeting trips like Magor/Somerton to Bristol/Cardiff, which I would suggest is very sensible.
 

Caaardiff

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The additional Bristol services proposed would be all-stations stoppers on the relief lines with five or six new stations. Even with EMUs and the expected relief line linespeed upgrades, these are unlikely to offer an attractive journey time for end-to-end journeys between Cardiff and Bristol. They are probably targeting trips like Magor/Somerton to Bristol/Cardiff, which I would suggest is very sensible.
There is no direct link from Swansea - Bristol Temple meads, without a change at Cardiff Central or Bristol Parkway. So the extra stops may not actually add that much journey time to a direct train from Swansea, than the time it would take to change and connect to a Temple Meads train.
 
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There is no direct link from Swansea - Bristol Temple meads, without a change at Cardiff Central or Bristol Parkway. So the extra stops may not actually add that much journey time to a direct train from Swansea, than the time it would take to change and connect to a Temple Meads train.
Also the idea behind the Swansea to Bristol trains is to call at the mainline stations (including the proposed 5) and offer an alternative to driving.
 

Caaardiff

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Also the idea behind the Swansea to Bristol trains is to call at the mainline stations (including the proposed 5) and offer an alternative to driving.
Many people from South Wales use Bristol Airport.

Swansea - Bristol Airport by train is 2hr40 with 2 changes, with about 15 mins change at Cardiff.
Swansea - Bristol Airport by road is just under 2 hours.

So just one change and a direct train to Temple Meads is more attractive than 2 changes.
 

anthony263

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Many people from South Wales use Bristol Airport.

Swansea - Bristol Airport by train is 2hr40 with 2 changes, with about 15 mins change at Cardiff.
Swansea - Bristol Airport by road is just under 2 hours.

So just one change and a direct train to Temple Meads is more attractive than 2 changes.
Plus Fridays especially it takes more than 2 hours to drive Swansea ti Bristol Airport I should know from experience
 

MikePJ

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More 197s will also come with the extra cost of a new, larger Depot to maintain them.
Only Chester do heavy maintenance of them which is at capacity, and can't see Canton taking that work on.
More Flirts make more sense as they are already maintained at Canton.
TFW should be looking into a direct link from Swansea to Bristol. Cardiff to Bristol is already well served.
Ah, very true about Canton.
 

43096

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So potentially thwn 231s diverted to these Bristol with 197s ordered to replace them on the Maesteg to Ebbw Vale services. People won't like that
Other than propping up basket case Welsh factories, why would they order more diesel only trains. It would be the height of stupidity to convert the 231s to electro-diesel and then back fill with new diesels. Just buy new electro-diesels from Stadler.
 

tfw756rider

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231s are EDMUs with a diesel tank and batteries, no overhead equipment
The 231s don't have (traction) batteries; they're simply DEMUs (diesel-electric multiple units), meaning that they're diesel multiple units (DMUs) that have electric transmission, where the wheels are driven by the electric traction motors that are powered via alternators that make the diesel engines act like generators (like the 220s/221s/222s, albeit with the engines in a separate vehicle),

as opposed to DHMUs (diesel-hydraulic multiple units, e.g. 158s) or DMMUs (diesel-mechanical multiple units, e.g. 197s) that are DMUs with hydraulic transmissions / mechanical gearboxes (respectively) that transfer the power from the engines to the wheels at changing ratios.

The hybridisation programme for the 231s would involve adding transformers and pantographs to them, so they'd become BMUs (bi-mode multiple units) like the 755s, in that they'd be able to put up their pantograph and take power from the overhead wires in the one mode, or from the diesel generators (as they already do) in the other,

but they'd still not have traction batteries like the tri-mode multiple unit (TMU) 756s do, so when "off the wires", they'd still only be able to run on their diesel engines (generating the power for their electric traction motors) rather than being able to run battery-electric / "diesel-less" like the 756s can.
 

AdamWW

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The 231s don't have (traction) batteries; they're simply DEMUs (diesel-electric multiple units), meaning that they're diesel multiple units (DMUs) that have electric transmission, where the wheels are driven by the electric traction motors that are powered via alternators that make the diesel engines act like generators (like the 220s/221s/222s, albeit with the engines in a separate vehicle),

as opposed to DHMUs (diesel-hydraulic multiple units, e.g. 158s) or DMMUs (diesel-mechanical multiple units, e.g. 197s) that are DMUs with hydraulic transmissions / mechanical gearboxes (respectively) that transfer the power from the engines to the wheels at changing ratios.

The hybridisation programme for the 231s would involve adding transformers and pantographs to them, so they'd become BMUs (bi-mode multiple units) like the 755s, in that they'd be able to put up their pantograph and take power from the overhead wires in the one mode, or from the diesel generators (as they already do) in the other,

but they'd still not have traction batteries like the tri-mode multiple unit (TMU) 756s do, so when "off the wires", they'd still only be able to run on their diesel engines (generating the power for their electric traction motors) rather than being able to run battery-electric / "diesel-less" like the 756s can.

I've seen it said of other diesel FLIRTS that in time the power car could just be removed to make them pure electrics so that may be the case here.
Or the diesels could perhaps replaced with battery modules to make the 231s into battery/overhead power trains.
I think the platform is quite versatile.
 

anthony263

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I was told that the 231s would have to return to Switzerland to be converted to bi mode

== Doublepost prevention - post automatically merged: ==

Other than propping up basket case Welsh factories, why would they order more diesel only trains. It would be the height of stupidity to convert the 231s to electro-diesel and then back fill with new diesels. Just buy new electro-diesels from Stadler.
Extra 231s or 756s would be what I would do however you know politicians.
 

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