Henley-on-Thames every 15 minutes

[SynthD]

This limited power could be insufficient to charge the batteries, which would require a fast charger; however, the existing third rail will lead to a very complex train, which is more likely to be unreliable, like the class 769s.

I see how installing the West Ealing charger in the third rail area could be complex, but what would be different about the train?

 

[BerkshireRails]

I see how installing the West Ealing charger in the third rail area could be complex, but what would be different about the train?

You have the risk of drawing power from both the third rail and the fast charger at the same time.

 

[Zomboid]

You have the risk of drawing power from both the third rail and the fast charger at the same time.

That sounds like a pretty simple thing to design out, with a break before make selector in the control/ charging circuit of the train.

 

[BerkshireRails]

That sounds like a pretty simple thing to design out, with a break before make selector in the control/ charging circuit of the train.

That is rather messy; there is a much simpler solution, which is just to electrify the line and upgrade the substations. It also has a good chance of failing.

 

[zwk500]

You have the risk of drawing power from both the third rail and the fast charger at the same time.

For the North Downs route you don't need a fast charger, there's enough time on the juice over the course of the day to maintain sufficient charge. Especially if you combine it with a c.1km extension of third rail at each junction for 'around the corner' power.

 

[BerkshireRails]

For the North Downs route you don't need a fast charger, there's enough time on the juice over the course of the day to maintain sufficient charge. Especially if you combine it with a c.1km extension of third rail at each junction for 'around the corner' power.

There is no chance of a third rail extension. Reading to Wokingham and the Guildford area have power supply issues, which require trains to only use notch 2 of power. On the third rail, the unit will not charge as fast as on a fast charger, plus North Downs gets to higher speeds, which makes it less attractive for use of batteries, and the higher frequency of North Downs Line services will only make the power supply issues worse. No Battery unit in the UK is fast enough, the North Downs gets up to 90mph in service and in the future it could go even faster with a plan to extend it from Reading to Oxford, which will allow it to do between 100-125mph in service depending on the line and the unit type used on the service.

 

[JonathanH]

the North Downs gets up to 90mph in service

Only for a short stretch between Redhill and Gatwick. The main bit is no more than 70mph.

a plan to extend it from Reading to Oxford

Not convinced by that. Where does the need and capacity for 8tph between Reading and Oxford come from?

 

[BerkshireRails]

Only for a short stretch between Redhill and Gatwick. The main bit is no more than 70mph.

There is a plan to extend 90mph running to more of the Downs.

 

[JonathanH]

There is a plan to extend 90mph running to more of the Downs.

How, and with whose money? It is a 70mph backwater with loads of stops in the same way the equally speedless line between Reading and Waterloo is.

 

[Bald Rick]

That sounds like a pretty simple thing to design out, with a break before make selector in the control/ charging circuit of the train.

That is rather messy; there is a much simpler solution, which is just to electrify the line and upgrade the substations. It also has a good chance of failing.

It’s not messy at all. Lots of places where trains are in contact with the AC OLE and DC third rail at the same time. What is the difference?

Reading to Wokingham and the Guildford area have power supply issues, which require trains to only use notch 2 of power. On the third rail, the unit will not charge as fast as on a fast charger, plus North Downs gets to higher speeds, which makes it less attractive for use of batteries, and the higher frequency of North Downs Line services will only make the power supply issues worse. No Battery unit in the UK is fast enough, the North Downs gets up to 90mph in service and in the future it could go even faster with a plan to extend it from Reading to Oxford, which will allow it to do between 100-125mph in service depending on the line and the unit type used on the service.

There is a plan to extend 90mph running to more of the Downs.

Literally none of the above is actually an issue, and much of it is not correct. For examl,e battery trains can easily achieve 125mph. Why do you think that is an issue?

And I can confirm there are no plans to have the North Downs at 90mph.

 

[BerkshireRails]

How, and with whose money? It is a 70mph backwater with loads of stops in the same way the equally speedless line between Reading and Waterloo is.

With the Surrey County Council's money. Fasts will certainly be able to get up to 90mph, considering of the 6 miles 77 chains between Redhill and Gatwick, only 3 miles 60 chains are passed for 90mph running.

It’s not messy at all. Lots of places where trains are in contact with the AC OLE and DC third rail at the same time. What is the difference?

The difference is they share the same return path, but it is still complex.

Literally none of the above is actually an issue. And I can confirm there are no plans to have the North Downs at 90mph.

The Surrey County Council report on the North Downs Line suggests otherwise. Also in a PWI video about West London Orbital, they said that no more electric trains could run on the Windsor Lines due to Grid feeder issues, hence why they are looking at run on Battery power from Acton Central to Hounslow and back, with the recharging happening between Acton Central and Brent Cross West while under the wires.

 

[Bald Rick]

The difference is they share the same return path, but it is still complex.

Quite correct, AC 25kV OLE and DC 750 3R do share the same return current path which makes it difficult.

DC750 3R and the Greenford trial ‘fast charge’ kit would not share the same return current path. That makes it much easier.

The Surrey County Council report on the North Downs Line suggests otherwise.

That has no bearing on ‘railway’ plans. Raising the speed of the North Downs might be desired by SCC, but it won’t be happening, and is not in any formal railway strategy or plans that I’m aware of.

Also in a PWI video about West London Orbital, they said that no more electric trains could run on the Windsor Lines due to Grid feeder issues

The Windsor lines in this case being those that the West London Orbital might run on. And not Wokingham to Reading, nor the Guildford area

 

[BerkshireRails]

The Windsor lines in this case being those that the West London Orbital might run on. And not Wokingham to Reading, nor the Guildford area

They said in the PWI video that they will have to be able to run to Willesden Junction via Whitton and Clapham Junction on battery power in case they can't go via South Acton. Wokingham to Reading uses the same feeder as Hounslow Loop, which is just controlled from two separate Electric Control Rooms.

That has no bearing on ‘railway’ plans. Raising the speed of the North Downs might be desired by SCC, but it won’t be happening, and is not in any formal railway strategy or plans that I’m aware of.

A more recent Network Rail report also suggests line speed increases for the North Downs, however it doesn't give a speed. Network Rail North Downs Line Report

Quite correct, AC 25kV OLE and DC 750 3R do share the same return current path which makes it difficult.

DC750 3R and the Greenford trial ‘fast charge’ kit would not share the same return current path. That makes it much easier.

This is an issue because if it draws maximum power from both the fast charger and the third rail at the same time, then it overloads the train's wiring and could cause a fire. This would block the railway, which would decimate services. If you're going to put a fast charger anywhere, put it where there is no other electrification. Also, OLE is the preferred fast charger as more battery networks are getting short sections of OLE, like at Caerphilly Bay on the Valley Lines, rather than using the GWR Fast Charger.

 

[cactustwirly]

All this talk about Battery trains and passing loops is pure fantasy

Current train service is perfectly adequate for the demand

 

[Bald Rick]

They said in the PWI video that they will have to be able to run to Willesden Junction via Whitton and Clapham Junction on battery power in case they can't go via South Acton. Wokingham to Reading uses the same feeder as Hounslow Loop, which is just controlled from two separate Electric Control Rooms.

The feeder isn’t the issue, it’s the distibution system capacity.

more recent Network Rail report also suggests line speed increases for the North Downs, however it doesn't give a speed. Network Rail North Downs Line Report

Read it again, and more carefully. It suggest journey time reductions, not line speed increases.

This is an issue because if it draws maximum power from both the fast charger and the third rail at the same time, then it overloads the train's wiring and could cause a fire.

I don’t think anyone is suggesting that the same train draws power from two systems at the same time. The suggestion is that the two systems can co-exist in the same location, and potentially could be used by the same train, but not concurrently. As happens 30-40 times an hour between Farringdon snd City Thameslink.

Also, OLE is the preferred fast charger as more battery networks are getting short sections of OLE, like at Caerphilly Bay on the Valley Lines, rather than using the GWR Fast Charger.

TfW specified the OLE electrification because it was compatible with the then already authorised OLE on the South Wales Main Line. It was also specified long before the GWR (formely Vivarail) system was brought to market.

There is absolutely no technical reason why a third rail battery train cannot be introduced. Which is just as well, as there are several running every day already.

 

[BerkshireRails]

Resd it again, and more carefully. It suggests journey time reductions, not line speed increases..

It says 'journey time benefits could be realised with a new traction technology and/or through efficient infrastructure decisions to realise modest line-speed increases'.

TfW specified the OLE electrificstion because it was compatible with the then already authorised OLE onthe South Wales Main Line. It was also specified long before the GWR (formely Vivarail) system was brought to market.

There is absolutely no techincsl reason why a third rail battery train cannot be introduced. Which is just as well, as there are several running every day already.

ORR will not allow new third rail areas, so Wales cannot even get third rail.

All this talk about Battery trains and passing loops is pure fantasy

Current train service is perfectly adequate for the demand

GWR really just wants to replace the Turbos on the London Thames Valley short branches with battery traction for environmental reasons, as then you can use them on lines which can make use of their higher top speed.

 

[AlastairFraser]

I think Henley definitely warrants wires. Marlow is a difficult case since it needs a really small train for the reversal. I wonder if a 40m long 25kV/ Battery high floor tram train style thing would be the answer for the whole area. Wire the various bay platforms from the main line and use those for charging and run them in pairs for the other branches. They could additionally be fitted with Greenford style charging for use in Devon & Cornwall if necessary.

In all honesty, Henley would be fine for a normal high floor tram with 4tph and restoration of the second Regatta line platform at Twyford/Henley (so you can have a second train leaving Twyford the minute the incoming train from Henley trundles in/vice versa).

It would be easier to achieve this at Twyford, but you'd probably have to convert the existing platform in Henley into an island platform and encroach a little on the car park (shouldn't be a massive issue, the current platform is pretty wide and the car park will still have a decent amount of spaces if you take away 10-20 for another track and a junction with the existing single track line).

Electrify to 750V DC tram spec to save money on electrification and build new basic tram stops at Bath Road near the sizeable Piggotts secondary school/Polehampton (to serve the sizeable residential developments on that side of Twyford/school traffic/Charvil) and a stop by Tescos on Mill Lane in Henley (serves the nearby residential developments and would be very useful during Regatta as the adjacent large supermarket car park could be used to support a park and ride scheme when Henley's normal car parks can't cope.)

 

[BlueLeanie]

Not convinced by that. Where does the need and capacity for 8tph between Reading and Oxford come from?

It depends on how you count it, but with two fasts, two semi/slow Oxford-Didcot & Didcot - Reading (split since electrification), and the traditional two XC services, then you have six already.

Then there's the planned extension of Chiltern services to new stations on the old Morris Cowley siding.

Now you have eight.

Then there's all kinds of speculation about E-W routes and the occasional Bristol service from Oxford.

 

[zwk500]

It says 'journey time benefits could be realised with a new traction technology and/or through efficient infrastructure decisions to realise modest line-speed increases'.

Which explicitly states *they don't have a plan for a specific option*. Normally 'modest' increases are achieved through raising PSRs to the ruling line speed.

ORR will not allow new third rail areas, so Wales cannot even get third rail.

Again not true, the ORR has set out the requirements to gain approval to install new third rail out. That they are not cost effective does not equal the ORR banning it.

 

[Zomboid]

In all honesty, Henley would be fine for a normal high floor tram with 4tph and restoration of the second Regatta line platform at Twyford/Henley (so you can have a second train leaving Twyford the minute the incoming train from Henley trundles in/vice versa).

It would be easier to achieve this at Twyford, but you'd probably have to convert the existing platform in Henley into an island platform and encroach a little on the car park (shouldn't be a massive issue, the current platform is pretty wide and the car park will still have a decent amount of spaces if you take away 10-20 for another track and a junction with the existing single track line).

Electrify to 750V DC tram spec to save money on electrification and build new basic tram stops at Bath Road near the sizeable Piggotts secondary school/Polehampton (to serve the sizeable residential developments on that side of Twyford/school traffic/Charvil) and a stop by Tescos on Mill Lane in Henley (serves the nearby residential developments and would be very useful during Regatta as the adjacent large supermarket car park could be used to support a park and ride scheme when Henley's normal car parks can't cope.)

There's no need to do DC, any electrification should be at 25kV and wouldn't need more than a switch and a short length of wiring, rather than a whole new electrification system.

These would be lightweight tram trains running at fairly low speeds so the energy requirement won't be especially high. I wouldn't be surprised if just wiring the relevant bay platforms was enough to keep batteries topped up between trips to Henley/ Marlow/ wherever else.

 

[cactustwirly]

It says 'journey time benefits could be realised with a new traction technology and/or through efficient infrastructure decisions to realise modest line-speed increases'.

ORR will not allow new third rail areas, so Wales cannot even get third rail.

GWR really just wants to replace the Turbos on the London Thames Valley short branches with battery traction for environmental reasons, as then you can use them on lines which can make use of their higher top speed.

Let's be real here, they will bulk order to replace all the turbos with something like FLIRTs. I highly doubt battery 230s will replace the turbos.

== Doublepost prevention - post automatically merged: 7 Jul 2025 ==

In all honesty, Henley would be fine for a normal high floor tram with 4tph and restoration of the second Regatta line platform at Twyford/Henley (so you can have a second train leaving Twyford the minute the incoming train from Henley trundles in/vice versa).

It would be easier to achieve this at Twyford, but you'd probably have to convert the existing platform in Henley into an island platform and encroach a little on the car park (shouldn't be a massive issue, the current platform is pretty wide and the car park will still have a decent amount of spaces if you take away 10-20 for another track and a junction with the existing single track line).

Electrify to 750V DC tram spec to save money on electrification and build new basic tram stops at Bath Road near the sizeable Piggotts secondary school/Polehampton (to serve the sizeable residential developments on that side of Twyford/school traffic/Charvil) and a stop by Tescos on Mill Lane in Henley (serves the nearby residential developments and would be very useful during Regatta as the adjacent large supermarket car park could be used to support a park and ride scheme when Henley's normal car parks can't cope.)

That's complete and utter fantasy, there is no need for 4tph. Henley is quite a small town

 

[BerkshireRails]

In all honesty, Henley would be fine for a normal high floor tram with 4tph and restoration of the second Regatta line platform at Twyford/Henley (so you can have a second train leaving Twyford the minute the incoming train from Henley trundles in/vice versa).

It would be easier to achieve this at Twyford. Still, you'd probably have to convert the existing platform in Henley into an island platform and encroach a little on the car park (shouldn't be a massive issue, the current platform is pretty wide and the car park will still have a decent amount of spaces if you take away 10-20 for another track and a junction with the existing single track line).

It would be better to put the loop in the Wargrave area and have it as a dynamic loop, as it would be halfway through the running time, making it easier to path. It would be really hard to get an attractive 4tph with two bays and Henley and Twyford, as they would have to follow one another on the single line. The units arrive at Henley at XX:27 & XX:57 and depart at XX:00 & XX:30, and arrive at Twyford at XX:12 & XX:42 and depart at XX:15 & XX:45.

 

[Benjwri]

It would be better to put the loop in the Wargrave area and have it as a dynamic loop, as it would be halfway through the running time, making it easier to path. It would be really hard to get an attractive 4tph with two bays and Henley and Twyford, as they would have to follow one another on the single line. The units arrive at Henley at XX:27 & XX:57 and depart at XX:00 & XX:30, and arrive at Twyford at XX:12 & XX:42 and depart at XX:15 & XX:45.

3 minute turn around is an absolutely fantasy during the regatta. They struggled hugely with 4 last week. With a passing loop all it takes is one issue to throw the service out unrecoverably.

 

[BerkshireRails]

3 minute turn around is an absolutely fantasy during the regatta. They struggled hugely with 4 last week. With a passing loop all it takes is one issue to throw the service out unrecoverably.

With a passing loop, it might be beneficial rather than trying to get a 4tph service; instead, aim for a 3tph service, then this would give you an 8-minute turnaround at Twyford and Henley while still providing a service enhancement. The passing loop would be around 2 miles long, so it would have the capacity to be used as a dynamic passing loop, and with longer turnaround times, it would help mitigate delays from being unrecoverable.

 

[Benjwri]

With a passing loop, it might be beneficial rather than trying to get a 4tph service; instead, aim for a 3tph service, then this would give you an 8-minute turnaround at Twyford and Henley while still providing a service enhancement. The passing loop would be around 2 miles long, so it would have the capacity to be used as a dynamic passing loop, and with longer turnaround times, it would help mitigate delays from being unrecoverable.

While this is true, ultimately it just isn’t needed. The Henley branch runs fine for the majority of the year. If it ever became overcrowded GWR could just use a 3 car, or two 4 cars.

The only problem days are the week days during the regatta. The Saturday service ran much better with the 7 car. I will admit this year the weekday service, especially Friday, was worse than ever in terms of queues, however this is solely constrained by GWR’s lack of Turbos. A 7 car service on a Friday should be possible, there would be some tighter pathing to work out around the peak extras in a weekday, but GWR were fairly confident they could make it work. This would null any need for doubling for capacity, at significantly less cost, as you would have to procure the units to double it in the first place.

 

[BerkshireRails]

Which explicitly states *they don't have a plan for a specific option*. Normally 'modest' increases are achieved through raising PSRs to the ruling line speed.

Which would be 70-90mph, because the North Downs Line runs to Gatwick Airport. The line speed in the Shalford Junction area is 85mph and 75mph.

Again not true, the ORR has set out the requirements to gain approval to install new third rail out. That they are not cost effective does not equal the ORR banning it.

Then why have Merseyrail gone for 777s with batteries if it is possible to extend the third rail on what is a grade-separated line?

Let's be real here, they will bulk order to replace all the turbos with something like FLIRTs. I highly doubt battery 230s will replace the turbos.

FLIRTs offer a worse capacity for units of similar length than the existing trains. A 3 Car 165 has 288 seats and is ~70m long, versus a 755/4, which only has 202 seats and is ~80m long. The North Downs Line is already quite busy to the point that you often have to stand because of a lack of seats, and you would want more bike spaces, as it isn't uncommon to see 10-20 bikes on a single train during the summer. The Maximum length of units on the Downs is around 4 cars due to Platform sharing at Redhill and multiple short platforms along the route, which can only fit 4 cars.

 

[Zomboid]

Which would be 70-90mph, because the North Downs Line runs to Gatwick Airport. The line speed in the Shalford Junction area is 85mph and 75mph.

Then why have Merseyrail gone for 777s with batteries if it is possible to extend the third rail on what is a grade-separated line?

FLIRTs offer a worse capacity for units of similar length than the existing trains. A 3 Car 165 has 288 seats and is ~70m long, versus a 755/4, which only has 202 seats and is ~80m long. The North Downs Line is already quite busy to the point that you often have to stand because of a lack of seats, and you would want more bike spaces, as it isn't uncommon to see 10-20 bikes on a single train during the summer. The Maximum length of units on the Downs is around 4 cars due to Platform sharing at Redhill and multiple short platforms along the route, which can only fit 4 cars.

It's not quite that straightforward though, 165s have 3+2 seating and 755s have 2+2, and they're not comparable in what their internal fit outs are trying to achieve.

 

[BerkshireRails]

While this is true, ultimately it just isn’t needed. The Henley branch runs fine for the majority of the year. If it ever became overcrowded GWR could just use a 3 car, or two 4 cars.

The only problem days are the week days during the regatta. The Saturday service ran much better with the 7 car. I will admit this year the weekday service, especially Friday, was worse than ever in terms of queues, however this is solely constrained by GWR’s lack of Turbos. A 7 car service on a Friday should be possible, there would be some tighter pathing to work out around the peak extras in a weekday, but GWR were fairly confident they could make it work. This would null any need for doubling for capacity, at significantly less cost, as you would have to procure the units to double it in the first place.

If only the branch were electrified, then a pair of 387s could be dedicated to the Branch during the regatta, freeing up Turbos for other roles. Suppose the track is slewed at Twyford and the points are moved closer to Henley. In that case, extending the platform to fit a 5- or 6-car turbo might be possible, which would keep its reliability but with extra capacity if electrification doesn't happen.

 

[HSTEd]

The cheapest option would probably be to get a Turbo or Sprinter retrofitted with a tube interior to add to the train on the Regatta weekend.

Find the least rusted out Class 150?

3 car Sprinter sandwiched between two two car Turbos so no need for traction knowledge

 

[BerkshireRails]

The cheapest option would probably be to get a Turbo or Sprinter retrofitted with a tube interior to add to the train on the Regatta weekend.

Find the least rusted out Class 150?

3 car Sprinter sandwiched between two two car Turbos so no need for traction knowledge

A minor issue is that 15Xs and 16Xs can't work with one another.

It's not quite that straightforward though, 165s have 3+2 seating and 755s have 2+2, and they're not comparable in what their internal fit outs are trying to achieve.

However, some of the work they do on route length is comparable.