Climbing The Valley Lines In The South Wales Metro
There are five terminal stations on the Cardiff Valley Lines, of which four will be served by battery-electric trains or tram-trains from Cardiff.
In this post, I will show how they will achieve this feat.
Consider.
- To get to Aberdare, Merthyr Tydfil or Treherbert, a tram-train must first get to Pontypridd.
- To get to Rhymney, a train must first get to Caerphilly.
I will now deal with the seven stations in alphabetic order.
Aberdare
This OpenRailwayMap shows the three branches of the Cardiff Valley Lines, that go through Pontypridd.
Note.
- Electrified lines are shown in red and unelectrified lines are shown in black.
- The branch to Aberdare is the middle of the three branches.
- It is planned that the service on the Aberdare branch will be provided using Class 398 tram-trains, that will be fitted with batteries.
- Electrification will be complete between Aberdare and Pontypridd.
It would appear that a tram-train could run between Aberdare and Pontypridd using the complete electrification.
Caerphilly
These two OpenRailwayMaps show the tracks through Caerphilly.
Note.
- The map on the left shows infrastructure, with the Rhymney Line shown in yellow.
- Caerphilly station is in the top third of the map.
- The white section of the Rhymney Line is the Caerphilly tunnel.
- The map on the right shows electrification, with the sections of the Rhymney Line that will be electrified are shown in red.
- Black sections will not be electrified.
- North of Caerphilly, the Rhymney Line is electrified, but through the station and the Caerphilly tunnel, there will be no electrification.
Trains will use battery power, where there is no electrification.
Ebbw Vale Town
This OpenRailwayMap shows the Ebbw Valley Railway.
Note.
- Electrified lines are shown in red and unelectrified lines are shown in black.
- Lines where electrification will be installed are shown in red and black.
- Newport is marked by the blue arrow.
- The North-South Line at the left is the Rhymney Line.
- The North-South Line in the middle is the Ebbw Valley Railway.
- The North-South Line at the right is the Marches Line to Hereford and Shrewsbury.
Trains will use diesel power on the Ebbw Valley Railway, as there is no electrification and no means of charging battery-electric trains.
It does seem strange that no electrified solution has been proposed for the Ebbw Valley Railway.
Consider.
- An Abertillery branch has been proposed.
- A Newport and Ebbw Vale Town service has been proposed and will be implemented.
- Perhaps the line is difficult to electrify.
It could just be, the electrifying the Ebbw Valley Railway, was a step too far.
Merthyr Tydfil
This OpenRailwayMap shows the three branches of the Cardiff Valley Lines, that go through Pontypridd.
Note.
- Electrified lines are shown in red and unelectrified lines are shown in black.
- The branch to Merthyr Tydfil is the rightmost of the three branches.
- It is planned that the service on the Merthyr Tydfil branch will be provided using Class 398 tram-trains, that will be fitted with batteries.
- Electrification will be complete between Merthyr Tydfil and Pontypridd, except for two short sections.
- I would assume that the short unelectrified sections can be handled using the tram-trains battery power.
It would appear that a tram-train could run between Merthyr Tydfil and Pontypridd using the electrification and the tram-trains batteries.
This shows the track layout at Quaker’s Yard station.
Note.
- Electrified lines are shown in red and unelectrified lines are shown in black.
- There are only two short length of electrification shown in the corners the map.
- Quaker’s Yard station has two platforms.
- The track layout appears to have single- and double-track sections.
It looks like it has been decided not to electrify this section. Perhaps, it was just too complicated to electrify easily?
This 3D Google Map shows the terminal station at Merthyr Tydfil.
It looks like the railway runs through the town to the station. So perhaps leaving out the electrification made everything safer?
Pontypridd
This OpenRailwayMap shows the tracks through Pontypridd.
Note.
- Electrified lines are shown in red and unelectrified lines are shown in black.
- Lines where electrification will be installed are shown in red and black.
- The line leaving the map in the South-East corner is the line to Cardiff.
- The line leaving the map in the North-West corner is the Rhondda Line to Treherbert.
- The line leaving the map in the North-East corner is the Merthyr Line to Aberdare and Merthyr.
Pontypridd stations lies at the junction of the three lines.
This OpenRailwayMap shows the platforms at Pontypridd.
Note.
- There are two long through platforms.
- There is a bay platform on the North side of the station for extra Cardiff services.
- The station is not electrified.
These pictures show Pontypridd station.
The station is Grade II Listed.
How will the tram-trains be powered through Pontypridd station?
Older Welsh railwaymen have told tales of how the coal trains from the mines in the valleys to Cardiff Docks were powered in part using gravity to propel the trains to the Docks. Steam locomotives then hauled the trains up the hills to get another load of coal.
Will Newton’s Friend be used to help the tram-trains return to Cardiff?
As the tram-trains descend, regenerative braking can be used to recharge the batteries.
A sophisticated computer control system, would choose the source of power from that which is available.
Descending from the terminal stations of Aberdare, Merthyr and Treherbert, and through Pontypridd would probably need a small amount of battery power to nudge the train to descend down the hill.
Fully-electrified stations like Aberdare and Treherbert will have the luxury of being able to use power from the electrification to start the descent.
Climbing the hills will be mainly on battery power, with the batteries being charged, where overhead electrification exists.
Rhymney
This OpenRailwayMap shows the Northern part of the Rhymney Line from Caerphilly to Rhymney.
Note.
- Electrified lines are shown in red and unelectrified lines are shown in black.
- Lines where electrification will be installed are shown in red and black.
- Caerphilly is marked by the blue arrow at the bottom of the map.
- Rhymney is at the Northern end of the rail line.
- Bargoed, Hengoed, Llanbradach and Caerphilly stations appear not to be electrified.
- It is planned that the service on the Rhymney Line will be provided using Class 756 trains, that will be fitted with batteries and diesel engines.
The Class 756 trains appear to have been designed to climb to Rhymney in all conditions, including a complete power cut. They will use batteries on the unelectrified sections of the climb.
Treherbert
This OpenRailwayMap shows the three branches of the Cardiff Valley Lines, that go through Pontypridd.
Note.
- Electrified lines are shown in red and unelectrified lines are shown in black.
- Lines where electrification will be installed are shown in red and black.
- The branch to Treherbert is the leftmost of the three branches.
- It is planned that the service on the Theherbert branch will be provided using Class 398 tram-trains, that will be fitted with batteries.
- Electrification will be complete between Treherbert and Pontypridd.
It would appear that a tram-train could run between Treherbert and Pontypridd when the electrification is complete.
Conclusion
Each of the five lines use their own methods of getting trains up the hills.
I suspect we’ll see some of the ideas used here on other stretches of electrification.
Taff’s Well Station – 22nd November 2023
I took these pictures as I passed through.
Note.
- A depot for the tram-trains is being built.
- The depot looks rather small.
- Four Class 398 tram-trains are lined up in the sidings of the depot.
- The last picture was taken four years ago , before any work started.
This OpenRailwayMap shows the depot.
Note.
- Electrified tracks are shown in red.
- Unelectrified tracks are shown in black.
- There are nine electrified sidings, which from my picture appear to be able to hold two tram-trains each.
- From other pictures on the web four of the unelectrified lines are covered tracks in the depot.
- The final two tracks seem to allow tram-trains to enter and leave the depot and these tracks are partially covered, there could be a washer alongside the building.
- The unelectrified Merthyr Line runs across the South-West corner of the map.
- Tram-trains will always enter the depot from the North.
- Tram-trains will always leave the depot to the North.
It is a slightly unusual layout for a depot, but it seems to fit well into a small site.
This OpenRailwayMap shows the Merthyr Line as it passes Taff’s Well Station and Depot.
Note.
- The Merthyr Line runs roughly North-West and South-East across the map.
- The Northern and Southern sections of the Merthyr Line are electrified, but the central section is not.
- Taff’s Well Depot is the red and black wart on the unelectrified section of the Merthyr Line.
- Tram-trains going North go to Pontypridd and then on to the three branch terminals at Treherbert, Aberdare and Merthyr Tydfil.
- Tram-trains going South go to Cardiff Central and Cardiff Queen Street stations.
Tram-trains use a mixture of overhead electrisation, battery power and assistance from Newton’s friend for power.
How A Tram-Train Arrives At Taff’s Well Depot
Consider.
- Tram-trains must approach Taff’s Well Depot from the North to enter the depot.
- This shouldn’t be a problem, as there appear to be crossovers at Pontypridd to transfer a tram-train to the right line if needed.
- As they descend from Pontypridd, any braking can be used to charge the batteries on the tram-trains.
- The track layout in the depot appears to allow any entering train to go into any track in the depot.
So depending on the work needed before the next trip, the tram-train can be efficiently placed in the right section.
How A Tram-Train Leaves Taff’s Well Depot
Consider.
- Tram-trains must leave Taff’s Well Depot to the North.
- As the Merthyr Line is not electrified, where the tram-trains leave the depot, they need to leave with enough power in the battery to reach the electrified section of the Merthyr Line.
- Tram-trains can only be charged in the nine electrified sidings.
So do the tram-trains, wait in the electrified sidings until, they have enough power in the batteries to do a circuit of the depot, join the Merthyr Line and go up the hill to the electrification?
If as I suspect, there is a tram-wash behind the depot, they can even take a pass through, so they enter service after a wash.
Conclusion
This could be a very efficient depot.
Pontypridd And The Station
I came back down to Pontypridd to take the line back up to Merthyr Tydfil.
I had a pleasant lunch there in the very busy Cafe Royal. I’ve never had a chicken curry, which contained very recognisable strips cut from a couple of large slices of chicken.
The station is at present having a ten million pound upgrade, which includes a new bay platform, so that extra trains can run to and from Cardiff.
Lifts and a new footbridge are also promised. There are full details here.
If Network Rail, their architects and buildings do their usual standard of work, then this could be a station of which the town can be very proud. Unlike many stations, it appeared to be right in the heart of the town.














































