The Anonymous Widower

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.

Rhymney Line

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?

June 6, 2018 - Posted by AnonW | Transport/Travel | Citylink, Class 399 Tram-Train, Class 755 Train, Keolis/Amey, South Wales Metro, Stadler, Stadler Citylink Metro Vehicle, Stadler Flirt, Tri-Mode Stadler Flirt