The Greening Of The Valleys
This document on the KeolisAmey web site details their plans for the new Wales and Borders Franchise.
The documents gives these two definitions.
- South Wales Metro – Includes the full set of local services around South East Wales. This includes what is currently known as the ‘Valley Lines’, plus services between Cardiff and Ebbw Vale, Maesteg and extending to Severn Tunnel Junction and beyond.
- Central Metro -Refers to the sub-set of the South Wales Metro train services which run from Treherbert, Aberdare, Merthyr Tydfil, Radyr, Rhymney and Coryton, through Queen Street to Cardiff Bay, Cardiff Central, Penarth, Barry Island and Bridgend.
For these services around Cardiff and on the Cardiff Valley Lines, KeolisAmey Wales intend to acquire the following fleet.
- 11 x four-car Stadler Flirt DEMU
- 7 x three-car Stadler Flirt Tri-mode MU
- 17 x four-car Stadler Flirt Tri-mode MU
- 36 x three-car Stadler Citylink Metro Vehicles
This diagram from the document shows the routes and the frequencies.
They also say the following surrounding the map in the document.
- Maintains all existing connections to Cardiff Queen Street and Cardiff Central stations.
- Service pattern easy to understand
- Most frequencies even in the hour ‘clockface’ (e.g. 00-15-30-45 past)
- Vale of Glamorgan, Barry, Penarth and City Lines integrated into Central Metro solution.
- 2tph from Pontypridd station ‘divert’ via City Line but don’t terminate at Central i.e. Aberdare – City Line – Central – Merthyr
Note that Aberdare, Merthyr Tydfil, Rhymney and Treherbert stations all get a total of four trains per hour (tph)
The Trains In More Detail
Stadler Rail are building the three fleets of rail vehicles.
Stadler Flirt DEMUs
Over a thousand Stadler Flirts have been sold to operators around the world. Most have been or will be built in Switzerland.
From the pictures, the trains, that will be delivered to Wales, look very much like the Class 755 trains, that have been ordered by Greater Anglia. These trains will enter service next year.
Stadler Flirt DEMUs gives more details of these trains and the closely-related fleets.
The trains will operate services between Cardiff and Ebbw Vale, Maesteg and extending to Severn Tunnel Junction and beyond.
Tri-Mode Stadler Flirts
I would expect that these trains are very similar to the bi-mode Flirt DEMUs, but that the power-pack would also contain a battery.
Tri-Mode Stadler Flirts gives more details of these trains and how I think they will operate.
The Tri-Mode Stadler Flirts are intended for Rhymney/Coryton <> Penarth/Barry Island/Bridgend via the Vale of Glamorgan Line.
There will be a lot of commonality between the two types of Flirts and I suspect driver and other staff training for the two variants will be the same.
Stadler Citylink Metro Vehicles
The Stadler Citylink Metro Vehicles in the KeolisAmey document. look very similar to Sheffield Supertram‘s Class 399 tram-trains, that are providing a tram service in Sheffield and will soon be running on the heavy rail network to Rotherham.
Stadler Citylink Metro Vehicles gives more details of these trains and how I think they will operate.
From Cardiff Queen Street To The Flourish
It looks like the Metro vehicles will use the batteries for power on the extension to the new terminal station at The Flourish.
I describe the proposal for the extension to the Flourish in The Flourish Station Is The Focus Of The South Wales Metro.
Electrically-Efficient Operation Of The Metro
I have a feeling that Stadler are bringing some of their mountaineering experience from Switzerland to the valleys of South Wales.
It is interesting that both the Tri-mode Stadler Flirts and the Stadler Citylink Metro Vehicles will have batteries.
Climbing The Hills
The main purpose of the batteries is to make the climb and descent to the terminals at the heads of the valleys as energy efficient as possible.
Efficient climbing of the hills will need all uphill tracks to be electrified.
The KeolisAmey document states this about the electrification.
Discontinuous overhead line electrification to 25 KVAC with permanently earthed sections around restricted structures, saving 55 interventions e.g. rebuilding bridges/no need for wire in Caerphilly tunnel.
Battery power would be invaluable for jumping the gaps in the electrification.
Coming down, I believe that the trains and tram-trains will use the batteries to handle the energy generated by regenerative braking.
This means.
- The electrification can be simpler.
- There might be no need to electrify the downhill track in double-track sections.
- Trains can use the battery power to cross sections without wires or restarting from stations, when going downhill.
- Tram-trains going to The Flourish will arrive at Cardiff Queen Street station with enough energy in the batteries for the return trip to The Flourish.
- The Cardiff Bay Line doesn’t need to be electrified, which saves money and possibly increases safety and reduces visual intrusion.
It is not only energy efficient, but it saves construction costs and time.
Why Aren’t Citylink Metro Vehicles Used On The Rhymney Line?
There are several possible reasons.
- Calculations have shown, that the battery capacity of the smaller Citylink vehicle might not be enough to go uphill through the Caerrphilly tunnel.
- The route may need more powerful vehicles.
- More capacity may be needed on this line, so the larger Tri-mode Stadler Flirts will be used.
- The Flirts could use their diesel engines to rescue a train stuck in the tunnel.
But whatever the reason, I’m sure it’s a good one!
Could Downhill Tracks Not Be Electrified?
I think this may be possible, as vehicles coming down the hills could use gravity and small amounts of battery power.
Regenerative braking would also be continuously charging the batteries.
It would certainly be simpler, than having to constantly swap between overhead and battery power on the descent, where the electrification was discontinuous.
As the lines are going to have a more intensive service, there will be additions of a second track in places to allow trains to pass.
Any electrification that could be removed from the project would be beneficial in terms of building and operational costs.
How Would Discountinuous Electrification Be Handled?
I discus this in How Can Discontinuous Electrification Be Handled?
The Lines In More Detail
Click these links to find out more about the individual lines.
Conclusion
The two types of compatible vehicles, allows the plans for the South Wales Metro to be a cost-effective and very green solution for Cardiff’s transport needs.
It is a model, that can be used elsewhere.
Will railway engineers in future talk of the Cardiff Model, just as they talk of the Karlsruhe Model?
More Information From The International Railway Journal About The New Wales And Borders Franchise
In Every Pair Of Pictures Tell A Story, I said I needed more information on what was happening with the new Wales and Borders franchise.
This article on the International Railway Journal is entitled £800m fleet renewal plan for new Welsh franchise, gives a lot more serious information.
These two paragraphs outline the plans.
According to the Welsh government, around £800m will be invested in rolling stock to ensure that by 2023, 95% of journeys will be made on a new fleet of 148 trains. The average age of the fleet will drop from 25 years to seven years by 2024.
More than half of the new trains will be assembled in Wales, indicating a major order will be placed with CAF, which is currently building a new assembly plant near Newport.
The article then goes on to make specific points.
Class 769 Trains
Class 769 trains will be used as a stop-gap measure until the arrival of new bi-mode trains.
Five of these trains are on order for delivery in the next eighteen months.
Class 230 Trains
Class 230 trains will join the fleet.
Perhaps they will be used on the Conwy Valley Line.
The line is rather isolated from depots at Cardiff, Chester and Machynlleth, which would find the Class 230 trains remote servicing capabilities useful.
The Wikipedia entry for KeolisAmey Wales states that the Class 230 trains will work the Borderlands Line, which will have a two trains per hour (tph) frequency.
As the journey takes an hour each way with a round trip possible in two hours, I suspect that a two tph frequency will need four trains, with perhaps a fifth one ready to step into service.
Again the remote servicing capability of the Class 230 train will come into play, as will the train’s affordability.
Class 170 Trains
Several Class 170 trains will join the fleet.
These could be coming from Greater Anglia, who currently have twelve of the trains, that will be replaced by Class 755 trains.
This page on the Welsh Government web site, contains this sentence.
On the Heart of Wales line, introduce refurbished Class 170 two-car units by 2022.
If you want to find out more about train services in Mid and South-West Wales, the page is well-worth a read.
Mark 4 Carriages
Mark 4 Carriages released from the East Coast Main Line will replace the current Mark 3 Carriages.
Phasing Out Of Diesel Multiple Units
The article makes these two points.
- Pacers will be withdrawn by the end of 2019.
- Class 150, Class 153, Class 158 and Class 175 trains will be completely replaced by 2023.
The only ones worth keeping could be the Class 158 trains, most of which if fitted with wi-fi would be acceptable on many routes.
New Diesel Multiple Units For Long Distance Services
The article says that new diesel multiple units will be introduced on these routes.
- North Wales Coast and Cambrian lines in 2022
- Milford Haven – Manchester route by 2023
This page on the Welsh Government web site, also says a new Swansea to Manchester service will be introduced from 2024.
In Every Pair Of Pictures Tell A Story, I suggested that Class 755 trains could be used on these routes.
- They have similar performance to the Class 175 trains.
- Length and power can be tailored for each route. Greater Anglia have ordered two sizes.
- As they are bi-modes, they could take advantage of the electrification East of Cardiff and around Birmingham and Manchester.
But the biggest thing in favour of Class 755 trains, is that the thirty-eight units for Greater Anglia are scheduled to be completed by the end of 2019. So if the Welsh trains are virtually identical to those for Greater Anglia, there would not be any serious certification problems.
The Wikipedia entry for KeolisAmey Wales indicates that these trains could be diesel versions of the CAF Civity.
The South Wales Metro
The IRJ article says that £738 million will be invested in this project.
The Wikipedia entry for KeolisAmey Wales gives a few more details of train frequencies.
- A new 1 train per hour (tph) Ebbw Vale to Newport service by May 2021.
- 2 tph between Cardiff and Bridgend via the Vale of Glamorgan Line from December 2023
- 4 tph throughout on the Rhymney line from December 2023
- 4 tph to Treherbert from December 2022
- 6tph to Cardiff Bay from December 2022
- 4 tph between Merthyr Tydfil, Aberdare and Cardiff from December 2022
This is an increase in frequency.
It appears there will be two distinct sections of this network, which I’ll discuss in the next two sub-sections.
An Electric Network On The Cardiff Valley Lines
The IRJ article says this.
A new fleet of low-floor vehicles offering level boarding will be introduced on the network by December 2022.
I think we can assume this about the vehicles.
- They will be tram-trains.
- They will have batteries.
- They will be able to use 750 VDC and 25 KVAC electrification.
- There will be a proportion of street running in Cardiff.
It would also be highly likely, that these vehicles will be built by CAF, in their new Newport factory. Wikipedia mentions a tram-train version of their Urbos trams, which are used in Edinburgh and the Midlands, which is called an Urbos TT.
A Complimentary Tri-Mode Network
The article says this.
A new fleet of Stadler “tri-mode” (electric/diesel/battery) multiple units will maintain links from Penarth, Barry and Bridgend to stations north of Cardiff Central. These trains will enter service from December 2023.
It looks from the pictures that these will be a version of the Class 755 trains.
In From Novara To Aosta, I described the route, where similar Stadler trains will be used on the Chivasso-Ivrea-Aosta railway to reach the town of Aosta. I would suspect that the Italian route could be more challenging, than anything South Wales has to offer.
The Heads Of The Valleys Stations Will Be Served By CAF’s Tram-Trains And Stadler Tri-Modes
It would appear from Wikipedia, that the stations at the heads of the valleys will have the following frequencies.
- 4 tph – Aberdare
- 2 tph – Ebbw Vale
- 4 tph – Merthyr Tydfil
- 4 tph – Rhymney
- 4 tph – Treherbert
These frequencies and some single-platform terminal stations, will mean that careful design must be applied, so that all vehicles have level access from platform to vehicle.
This picture shows the access to a Stadler Flirt in Italy.
Note the gap filler, which automatically moves into place.
I’m sure engineers and designers working for KeolisAmey, CAF and Stadler can come up with a very good solution.
Will The Valley Lines Be Electrified With 25 KVAC?
I think it is highly likely that CAF’s vehicles for the tram section of the South Wales Metro will be tram-trains with a dual 750 VDC/25 KVAC capability and batteries.
Imagine one of these vehicles climbing to say Aberdare using the Merthyr Line, which is a mixture of single and double-track to Cardiff.
Going up to Aberdare, due to the gradients, the vehicles will need access to electrical power, so electrification is necessary, unless each vehicle has a massive diesel generator or ultra-large battery, which are respectively not very environmentally friendly or practical.
But I doubt it will matter if the electrification is 750 VDC or 25 KVAC.
Going down the valley to Cardiff, I believe that CAF’s vehicles will use Newtons friend; gravity and regenerative braking to control the speed. The energy generated by the braking would be stored in an onboard battery.
CAF have all the technology and it would be extremely energy efficient.
The Stadler tri-modes would have to use diesel on the way up, but given they have batteries, I suspect they’d come down in a similar way to the CAF tram-trains.
So what voltage should be used?
- The CAF tram-trains will probably be able to use either voltage.
- If batteries are used to handle regenerative braking, this works with all voltages.
- The Stadler tri-modes will probably need 25 KVAC.
- Electrifying with 25 KVAC would allow the Stadler tri-modes to avoid a lot of running on diesel.
- Any electric locomotives hauling freight would need 25 KVAC.
I wouldn’t be surprised to see the valley lines electrified with 25 KVAC.
Will Only The Uphill Tracks Be Electrified?
I believe that if trains coming down the valleys use batteries for regenerative braking and restarting at stations, it may be possible to only electrify a single-track, that is always used for uphill trains.
But only the tracks for uphill trains were electrified, this would make the works easier and reduce costs and disruption to passengers.
Conclusion
It looks like KeolisAmey have got a well thought-out plan!
The Anonymous Widower 