Global Warming - Time to Crack on with Electrification?

Envoy · 13 Aug 2026

With Global Warming increasing the likelihood of heatwaves and droughts, surely it is high time that the UK Government authorised the roll out of more lines being electrified?

Currently, we have a situation where trains that can run on electricity - such as the Hitachi 800 series - are running on diesel power over extensive distances. This is true for the entire south-west where the overhead wires end at Newbury and at Chippenham on the route to Bath and Bristol. Both the south-Wales (west of Cardiff) and Crewe to north Wales main lines also have the Hitachi trains running on their diesel engines.

The London (Waterloo) to Exeter route has ancient Class 159 trains running on diesel. Old diesel trains also operate on the busy route that links Cardiff > Bristol > Bath > Salisbury > Southampton & Portsmouth. In the north, there are numerous routes still operating with diesel trains. In addition are the busy diesel operated routes operated by Cross Country linking the north and south of the country. All of these routes are going to need stock replacement.

Wales has shown how discontinuous electrification with neutral sections under some bridges plus the use of stored battery power on trains like the Class 756 Stadler Flirts can reduce the cost of electrification. I find it incredible that other advanced countries appear to have a greater proportion of lines electrified than Britain. The way things are going with the gradual take up of electric cars, road transport will be more ‘green’ than rail travel.

RailUK Forums

zwk500 · 13 Aug 2026

Envoy said:
Wales has shown how discontinuous electrification with neutral sections under some bridges plus the use of stored battery power on trains like the Class 756 Stadler Flirts can reduce the cost of electrification.

Are there independent sources for approximate costs per single track kilometre in Wales, England (case-by-case individual project approval) and Scotland (rolling programme)?

In answer to the thread question - Yes! Really the time was long ago, but we can't redo the past so no time like the present. Batteries will absolutely be part of the electrification solution, but there's plenty of lines where OLE is worthwhile.

The Planner · 13 Aug 2026

Envoy said:
With Global Warming increasing the likelihood of heatwaves and droughts, surely it is high time that the UK Government authorised the roll out of more lines being electrified?

Currently, we have a situation where trains that can run on electricity - such as the Hitachi 800 series - are running on diesel power over extensive distances. This is true for the entire south-west where the overhead wires end at Newbury and at Chippenham on the route to Bath and Bristol. Both the south-Wales (west of Cardiff) and Crewe to north Wales main lines also have the Hitachi trains running on their diesel engines.

The London (Waterloo) to Exeter route has ancient Class 159 trains running on diesel. Old diesel trains also operate on the busy route that links Cardiff > Bristol > Bath > Salisbury > Southampton & Portsmouth. In the north, there are numerous routes still operating with diesel trains. In addition are the busy diesel operated routes operated by Cross Country linking the north and south of the country. All of these routes are going to need stock replacement.

Wales has shown how discontinuous electrification with neutral sections under some bridges plus the use of stored battery power on trains like the Class 756 Stadler Flirts can reduce the cost of electrification. I find it incredible that other advanced countries appear to have a greater proportion of lines electrified than Britain. The way things are going with the gradual take up of electric cars, road transport will be more ‘green’ than rail travel.

Politics

Snow1964 · 13 Aug 2026

Envoy said:
This is true for the entire south-west where the overhead wires end at Newbury and at Chippenham on the route to Bath and Bristol. Both the south-Wales (west of Cardiff) and Crewe to north Wales main lines also have the Hitachi trains running on their diesel engines.

The London (Waterloo) to Exeter route has ancient Class 159 trains running on diesel. Old diesel trains also operate on the busy route that links Cardiff > Bristol > Bath > Salisbury > Southampton & Portsmouth. In the north, there are numerous routes still operating with diesel trains.

On Chippenham-Bristol section, a lot of the clearance work was done, and some masts erected (still standing, doing nothing)

Cardiff-Portsmouth is electrified both ends (Cardiff-Patchway and Redbridge-Portsmouth)

The section from Filton-Bristol-Bathampton has 5+ trains each way per hour, and whilst cost of doing low frequency routes will struggle, not being able to justify a route with 5+ trains per hour is bonkers.

Waterloo-Exeter has about 50 miles electrified, and a small patch of wiring from Salisbury to Wilton would allow all the Salisbury terminators and the Cardiff-Portsmouth to be regional BEMU operated (not that there are any yet).

But in general a few miles in big gaps would allow regional BEMUs. As another example if Gloucester-Cheltenham area was done then then services like Bristol-Worcester, or Cardiff-Cheltenham or XC Bristol-Manchester could also switch to BEMU. But at the moment it seems 35+ year old diesels with no replacements on order is the plan. But why Government thinks that is a good long term plan is beyond my understanding

kevjs · 13 Aug 2026

Envoy said:
With Global Warming increasing the likelihood of heatwaves and droughts, surely it is high time that the UK Government authorised the roll out of more lines being electrified?

Currently, we have a situation where trains that can run on electricity - such as the Hitachi 800 series - are running on diesel power over extensive distances. This is true for the entire south-west where the overhead wires end at Newbury and at Chippenham on the route to Bath and Bristol. Both the south-Wales (west of Cardiff) and Crewe to north Wales main lines also have the Hitachi trains running on their diesel engines.

The London (Waterloo) to Exeter route has ancient Class 159 trains running on diesel. Old diesel trains also operate on the busy route that links Cardiff > Bristol > Bath > Salisbury > Southampton & Portsmouth. In the north, there are numerous routes still operating with diesel trains. In addition are the busy diesel operated routes operated by Cross Country linking the north and south of the country. All of these routes are going to need stock replacement.

Wales has shown how discontinuous electrification with neutral sections under some bridges plus the use of stored battery power on trains like the Class 756 Stadler Flirts can reduce the cost of electrification. I find it incredible that other advanced countries appear to have a greater proportion of lines electrified than Britain. The way things are going with the gradual take up of electric cars, road transport will be more ‘green’ than rail travel.

The UK's 8th, 10th, and 11th largest cities and the centre of the 9th largest city (Nottingham, Sheffield, Leicester, and Bristol) are all served solely by diesel traction. Completing the electrification of a single railway line (the Midland Mainline) would change that for three of those cities, and - assuming they can get the new trains working reliably - the intercity fleet would be able to utilise any extensions from day 1. That seems to be a very low lying fruit to get more electrification rolled out and remove the dependency on diesel.

With the roll out of electric buses and electric service vehicles, and gradual transition to electric cars in Nottingham it's quiet possible that within the next ten to fifteen years our railway station will become our biggest pollution hotspot (it's already one of them). Our regions (East Midlands) regional rail fleet has around another 15 - 25 years of life in it, meaning that by the time the electrification is complete on the mainline it would probably be worth ensuring the new regional fleet is all hybrid to make use of it.

Magdalia · 13 Aug 2026

Envoy said:
With Global Warming increasing the likelihood of heatwaves and droughts, surely it is high time that the UK Government authorised the roll out of more lines being electrified?

No.

The Government already has a lot of debt. It has to pay 4.5-5% interest on new debt, so it doesn't have the finance to do much more over and above HS2, EWR, TransPennine, and what else was in the 2025 spending review.

I expect that there will be another spending review after the October 2026 budget. In that, the government is going to have to fund increased defence spending as first priority. In terms of investing to meet the impact of climate change, water and the NHS need investment more than rail transport.

Furthermore, the new emphasis on devolution means that any new future transport infrastructure investment is going to prioritise "growth in every postcode", with mayors influencing priorities on a regional basis.

For rail decarbonisation, the priority has to be new electric/battery bimode trains. Limited amounts of discontinuous electrification will be needed to facilitate the use of those electric/battery bimode trains on more routes, especially those where mayors want improved services to help deliver economic growth. That will be quicker, cheaper and more cost effective than traditional whole route electrification.

The priority is to get on with designing and building the new electric/battery bimode trains, preferably funded in a way that's off the government balance sheet!

EuxtonNeutral · 13 Aug 2026

Envoy said:
The way things are going with the gradual take up of electric cars, road transport will be more ‘green’ than rail travel.

Very true that we need more rail electrification to decarbonise transport.

However as Gareth Dennis tirelessly points out, this is primarily because electrification enables more modal shift from road/air to rail, because it massively increases capacity.

This is a more important reason for electrification that to decarbonise the trains themselves (except at stations where diesels sitting are noxious).

It’s probably not true that electrifying the whole of the UK’s private car fleet would make road greener than rail, even if we kept the diesels, because of all the embodied carbon/rare earths etc in the millions of batteries that will be required. Trains are primarily green because of efficient running (steel on steel) and economy of scale. Of course electric trains are even greener on both counts. But even diesels are arguably greener than (new) EVs.

== Doublepost prevention - post automatically merged: 13 Aug 2026 ==

EuxtonNeutral said:
(except at stations where diesels sitting are noxious).

Viz. Euston, which stinks again now dirty Lumo have got their way.

== Doublepost prevention - post automatically merged: 13 Aug 2026 ==

EuxtonNeutral said:
It’s probably not true that electrifying the whole of the UK’s private car fleet would make road greener than rail, even if we kept the diesels, because of all the embodied carbon/rare earths etc in the millions of batteries that will be required

Also you have to factor in other negative externalities of road traffic vs rail: safety, noise pollution, hogging and diminishing the public realm etc.

napierdeltic · 13 Aug 2026

Why because of heatwaves and droughts do we need to electrify? Very odd question. Are you thinking of global warming as its too late for that now.

Country is £3 trillion in debt because of borrowing money and pervious governments trying to play a balancing act. Only increase taxes will extra money be available for more important things rather than electrifying.

JonathanH · 13 Aug 2026

EuxtonNeutral said:
It’s probably not true that electrifying the whole of the UK’s private car fleet would make road greener than rail, even if we kept the diesels, because of all the embodied carbon/rare earths etc in the millions of batteries that will be required.

While steel for electrification isn't so much about rare earth metals, there is still embodied carbon in its production. I agree that rare earth metals is a problem though.

napierdeltic said:
Country is £3 trillion in debt because of borrowing money and pervious governments trying to play a balancing act. Only increase taxes will extra money be available for more important things rather than electrifying.

With regard to debt, I think we also need to be conscious of where the supply chain is for the different courses of action and which involves more imported products to fulfil.

AndrewE · 13 Aug 2026

napierdeltic said:
Why because of heatwaves and droughts do we need to electrify? Very odd question. Are you thinking of global warming as its too late for that now.

Country is £3 trillion in debt because of borrowing money and pervious governments trying to play a balancing act. Only increase taxes will extra money be available for more important things rather than electrifying.

and you think that the costs of doing nothing won't be higher than decarbonising? Lots of savings to be had through better health alone - directly from reduced pollution and indirectly from fitter people if they can be tempted on to active transport.
Look at the costs of this year's fires too...

Harpo · 13 Aug 2026

Better use of the electrification that we have got would be a good start.

The exile · 13 Aug 2026

napierdeltic said:
Why because of heatwaves and droughts do we need to electrify? Very odd question. Are you thinking of global warming as its too late for that now.

You do realise that global warming is a continuous process? At the moment “doing something about it” might actually still have an effect in the medium term. The real danger we face is sticking our fingers in our ears going “la-la-la” until we reach the tipping point when the rate at which global warming feeds itself is unstoppable. At that point, government debt will be the least of our worries.

Trainbike46 · 13 Aug 2026

I think this is a bit an "all of the above" situation.

We need to order BEMUs for the many routes that already have all the electrification needed for them.

We need to place an order for diesel/battery/OHLE/third rail tri-modes for XC (and bin the voyagers).

We need power supply upgrades on existing electrification to enable the above and to end the situation where bimodes use diesel under the wires.

We need a plan for targeted electrification, to enable BEMU operation on those routes where it isn't currently possible, and then we need to get started on rolling that out.

And all of the above needs to be done in a way that enables and encourages passenger growth while decreasing per-passenger operational costs.

brad465 · 13 Aug 2026

Decarbonising rail should be done where it can enhance the capacity of routes that draw lots of traffic off the roads, as road transport is where the large emissions are. For example, Exeter-Bromsgrove would be good to electrify at least enough for everything to be battery-electric, as this runs parallel to the M5. The Chiltern mainline likewise for the M40. The TransPennine upgrade is already doing this in relation to the M62, while HS2 (one hopes), for the M1 and M6 (if Manchester ever gets reinstated).

Magdalia · 13 Aug 2026

brad465 said:
Decarbonising rail should be done where it can enhance the capacity of routes that draw lots of traffic off the roads, as road transport is where the large emissions are.

But the case for this is getting weaker because road traffic is also decarbonising with increased use of electric vehicles.

HSTEd · 13 Aug 2026

Envoy said:
Wales has shown how discontinuous electrification with neutral sections under some bridges plus the use of stored battery power on trains like the Class 756 Stadler Flirts can reduce the cost of electrification. I find it incredible that other advanced countries appear to have a greater proportion of lines electrified than Britain. The way things are going with the gradual take up of electric cars, road transport will be more ‘green’ than rail travel.

The window for extensive electrification has, I think closed.

Battery systems are now good enough that the "neutral sections" can be tens of kilometres long, at which point I'm not sure how much additional electrification we would actually need. Some certainly, but not enough to justify an enormous rolling programme.

The railway has repeatedly failed to deliver electrification at a reasonable cost, and I don't think its reasonable to expect the government to keep trying endlessly. Some short amounts of electrification in places like Sheffield, Plymouth and elsewhere to enable battery operations will be required, but beyond that I would not expect much else.

The Planner · 13 Aug 2026

EuxtonNeutral said:
Very true that we need more rail electrification to decarbonise transport.

However as Gareth Dennis tirelessly points out, this is primarily because electrification enables more modal shift from road/air to rail, because it massively increases capacity.

This is a more important reason for electrification that to decarbonise the trains themselves (except at stations where diesels sitting are noxious).

That's doing some heavy lifting.

EuxtonNeutral said:
Viz. Euston, which stinks again now dirty Lumo have got their way.

They haven't, the couldn't run north of Crewe currently with electrics.

HSTEd · 13 Aug 2026

EuxtonNeutral said:
It’s probably not true that electrifying the whole of the UK’s private car fleet would make road greener than rail, even if we kept the diesels, because of all the embodied carbon/rare earths etc in the millions of batteries that will be required. Trains are primarily green because of efficient running (steel on steel) and economy of scale. Of course electric trains are even greener on both counts. But even diesels are arguably greener than (new) EVs.

As a climate resarcher, I am very sceptical of this.

Embodied emissions are a significant quantity of carbon, yes, but pale in comparison to the shear quantities of carbon emitted by burning diesel.

Burning a single tank of diesel (~1750L) on a single Class 158 vehicle releases ~4.4 tonnes of carbon dioxide, not counting life cycle emissions in production of the diesel.
A quick google suggests embodied emissions from an EV are about 10-15 tonnes. So you could build an EV for every one of the ~70 seats in the vehicle in about 150-225 tanks of diesel. Which an intensively used modern DMU will probably run up quite quickly.

JonathanH · 13 Aug 2026

HSTEd said:
As a climate resarcher, I am very sceptical of this.

Embodied emissions are a significant quantity of carbon, yes, but pale in comparison to the shear quantities of carbon emitted by burning diesel.

Burning a single tank of diesel (~1750L) on a single Class 158 vehicle releases ~4.4 tonnes of carbon dioxide, not counting life cycle emissions in production of the diesel.
A quick google suggests embodied emissions from an EV are about 10-15 tonnes. So you could build an EV for every one of the ~70 seats in the vehicle in about 150-225 tanks of diesel. Which an intensively used modern DMU will probably run up quite quickly.

How long is the payback period for the steel and other work involved in railway electrification from a carbon point of view, assuming 'green' energy from the point electrified services start, but including the cost of building the extra power generation?

HSTEd · 13 Aug 2026

JonathanH said:
How long is the payback period for the steel and other work involved in railway electrification from a carbon point of view, assuming 'green' energy from the point electrified services start, but including the cost of building the extra power generation?

That question is inherently difficult to answer, especially the part about "extra power generation".

But the payback period otherwise will be very short. However, I don't think the carbon payback is the issue holding back railway electrification, I think it is the inability of the railway to deliver it at acceptable cost and on an acceptable schedule.

EDIT:

The RSSB estimates that railway electrification would require 313 tonnes of carbon dioxide equivalent per route mile for a twin track railway. That's about 125,000 litres of diesel per route mile or 38,900 litres per track kilometre.

Over one mile of railway typically there will be an OLE structure every 50m, resulting in embodied carbon emissions of 107 tonnes CO2e. A total of 70 foundations will be required for these structures, adding carbon emissions of 160 tonnes CO2e. The impact of wires along one mile of railway is 47 tonnes CO2e (for catenary, contact, earth, auto-transformer and return conductor wires), giving a total value of 313 tonnes CO2e for the materials required to electrify one mile of standard railway.

EDIT: As I recall, a Class 170 uses about 0.4 litres of fuel per vehicle-kilometre, which suggests about 100,000 vehicles would have to pass over a twin track railway per direction to pay back the electrification carbon.

EDIT #2: mean 100,000 vehicles, not trains, have corrected.

eldomtom2 · 13 Aug 2026

HSTEd said:
EDIT: As I recall, a Class 170 uses about 0.4 litres of fuel per vehicle-kilometre, which suggests about 100,000 vehicles would have to pass over a twin track railway per direction to pay back the electrification carbon.

That's not a lot - with 30 trains a day you pay that back in less than ten years.

GRALISTAIR · 13 Aug 2026

The Planner said:
Politics

Only 3 things you ever need (imho)

Time
Money
Political will

eldomtom2 · 13 Aug 2026

GRALISTAIR said:
Only 3 things you ever need (imho)

Time

Money

Political will

Not that these things are unrelated to each other, of course - the quicker and cheaper something is the easier to get political support for it.

Dr Hoo · 13 Aug 2026

Whilst some extensions will obviously help I would give more urgent attention to strengthening power supplies on the existing routes.
We will need to support:
More or longer passenger trains to accommodate growth;
Electric haulage of freight, including a 75% volume uplift; and
Heavier loads for better air conditioning and topping up bi-mode batteries whilst also drawing traction power.

I have no idea where the ‘extra capacity’ is coming from. Taking the St Pancras lines for example; we’re stuck with three platforms for ‘inter-city’ services of 10 cars whether they’re diesel, bi-mode or pure EMU. And EMUs are useless once you need to divert via Manton, Castle Donington, the Erewash Valley or Barrow Hill (or when the wires are down like they are this evening).

zwk500 · 13 Aug 2026

GRALISTAIR said:
Only 3 things you ever need (imho)

Time

Money

Political will

And 2 is arguably part of 3.

AndrewE · 13 Aug 2026

And what do we think of the people taking a high-level overview, who say that we need to put all our economies onto a war-footing (e.g. https://www.bbc.co.uk/news/uk-59115203) if we are going to have any effect?
I'm with them, and think that the Treasury needs to be made subservient to the Environment dept (a very radicalised one.)

GRALISTAIR · 13 Aug 2026

AndrewE said:
And what do we think of the people taking a high-level overview, who say that we need to put all our economies onto a war-footing (e.g. https://www.bbc.co.uk/news/uk-59115203) if we are going to have any effect?
I'm with them, and think that the Treasury needs to be made subservient to the Environment dept (a very radicalised one.)

In theory there is no need. The Prime Minister is 1st Lord of the Treasury and the Chancellor the 2nd Lord.

KHCT · 13 Aug 2026

Given that 'global warming' is a global issue, and UK rail emissions are a tiny part of the UK's tiny part of global emissions, you could electrify the lot tomorrow and it would make precisely zero difference to this global issue. There may be many good reasons for further electrification, but an overreaction to a warm summer isn't one of them.

I'd say it's reasonable to build a case to electrify the trunk Intercity network, but there will never be a sound economic case for most branch and secondary routes.

HSTEd · 13 Aug 2026

AndrewE said:
And what do we think of the people taking a high-level overview, who say that we need to put all our economies onto a war-footing (e.g. https://www.bbc.co.uk/news/uk-59115203) if we are going to have any effect?
I'm with them, and think that the Treasury needs to be made subservient to the Environment dept (a very radicalised one.)

A "war-like footing" for decarbonisation will have to husband its available industrial and economic resources to achieve maximum effect.

Heavy rail electrification seems highly unlikely to achieve that - after all only a fifth of the UK rail vehicle fleet is diesel as it is.
A few billion on battery electric trains and the network is likely largely electrified - and subsidising underground mining of aggregates in the south east would take a huge chunk out of the railways diesel freight traffic.

I think any decarbonisation rail investment is probably going to be focussed on light rail and light rail conversions of underutilised heavy rail infrastructure.

deltic08 · 14 Aug 2026

For a start, Lumo should not have been allowed to run a service from Stirling to London using diesel trains entirely under wires. They should have been made to wait until electric trains are available. It makes a mockery of decarbonisation.
Discontinuous electrification might help reduce initial installation costs but costs just as much if not more than continuous electrification to propel a train with bimodes costing more to build and maintain than straight electrics. Copper overhead wires need to be of heavier section (more expensive than normal wires) as the train takes normal power but extra to recharge almost fully discharged batteries on the move. As supply is interrupted, more feeder stations are required for resilience as a section of overhead wire cannot be fed from either end so two feeder stations needed one at each end. There is greater risk of a pan becoming entangled in the oncoming end of overheads or fully extended into over bridges at the run off end.

Global Warming - Time to Crack on with Electrification?

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