Brighton Main Line improvements

[Verulamius]

Network Rail has published this month (April 2026) a summary strategy document with options on improving the Brighton main line (BML).

https://sacuksprodnrdigital0001.blob.core.windows.net/regional-long-term-planning/Southern%20region%20-%20planning%20documents/Brighton%20Main%20Line%20Strategy%20Summary%202026.pdf

The report is redacted so that it does not show all the detailed numbers, but it is clearly recommending a future approach for improvements. It reads as initial proposals to DfT/HM Treasury to enable more work to be undertaken to work up the proposals in more detail.

The BML will become increasingly congested by the late 2030s, with the bottleneck around Croydon a constraint to strategic service growth across the BML, MML and ECML. This report explains the choices available to government and industry, highlights the consequences of inaction, and recommends a pathway that supports sustainable growth across the South East. Without a decisive investment strategy, economic growth, network reliability, financial sustainability and the region’s international competitiveness are at risk.

Recommended approach is to gradually build up additional passenger capacity, through more trains and improved infrastructure, as and when required. The two extreme solutions are to do avoid infrastructure improvements or to transform the railway.

 

[Turtle]

Network Rail has published this month (April 2026) a summary strategy document with options on improving the Brighton main line (BML).

https://sacuksprodnrdigital0001.blob.core.windows.net/regional-long-term-planning/Southern%20region%20-%20planning%20documents/Brighton%20Main%20Line%20Strategy%20Summary%202026.pdf

The report is redacted so that it does not show all the detailed numbers, but it is clearly recommending a future approach for improvements. It reads as initial proposals to DfT/HM Treasury to enable more work to be undertaken to work up the proposals in more detail.



Recommended approach is to gradually build up additional passenger capacity, through more trains and improved infrastructure, as and when required. The two extreme solutions are to do avoid infrastructure improvements or to transform the railway.

View attachment 203005

This makes one realise how shortsighted it was to cancel the East Croydon-Norwood Junction improvement plan a few years ago.

 

[Bald Rick]

This makes one realise how shortsighted it was to cancel the East Croydon-Norwood Junction improvement plan a few years ago.

Define “shortsighted”

 

[weeklycommuter]

I do not know why page 4 lists Transport for the South East as a strategic stakeholder. I thought TfSE funding was going to end in March 2027 so TfSE will cease to exist.

The document does note that Local government reorganisation is underway to qualify the list of councils in footnote 1 but Brighton & Hove is not a Combined Authority.

Noting the spelling error "Straetgic Connectivity" under Transport for the South East (TfSE) missions I wonder how carefully this document was checked.

 

[JonathanH]

This makes one realise how shortsighted it was to cancel the East Croydon-Norwood Junction improvement plan a few years ago.

I'm not sure it does. Even under the timetable it doesn't suggest that work would proceed for another ten years, with completion a further ten years away. It looks like other less costly interventions are possible before then.

 

[Nicholas Lewis]

Unless there is significant disruption the Thameslink 12 car 700's provide plenty of capacity up to London Bridge from East Croydon currently. Its the Clapham Jcn/Victoria service that are full and standing off East Croydon and this can be easily fixed by getting everything back upto 12 cars before big infrastructure intervention is needed. If growth continues beyond then infrastructure interventions maybe back on the agenda but the wildcard here is what AI does to the London jobs market and thus commuting.

 

[cle]

Unless there is significant disruption the Thameslink 12 car 700's provide plenty of capacity up to London Bridge from East Croydon currently. Its the Clapham Jcn/Victoria service that are full and standing off East Croydon and this can be easily fixed by getting everything back upto 12 cars before big infrastructure intervention is needed. If growth continues beyond then infrastructure interventions maybe back on the agenda but the wildcard here is what AI does to the London jobs market and thus commuting.

Agreed. And this applies across the network. But is especially poignant for an existing 12 car network, (10 for inners) which Southern is.

Absorbing and standardizing Gatwick Express would also help add to the core route - whether they call at Clapham or Croydon but ideally both -

even if we have to lose 1 tph, and even out the path gaps so that it adds 3tph to Vic-CJ-EC-Gatwick - that would be a net benefit IMO.

 

[rmHawk765]

'24tph Thameslink' instead of fixing the mess that is the ECML at the minute...

Seriously, where are they planning to send that extra 4tph?

 

[izvor]

Unless there is significant disruption the Thameslink 12 car 700's provide plenty of capacity up to London Bridge from East Croydon currently. Its the Clapham Jcn/Victoria service that are full and standing off East Croydon and this can be easily fixed by getting everything back upto 12 cars before big infrastructure intervention is needed. If growth continues beyond then infrastructure interventions maybe back on the agenda but the wildcard here is what AI does to the London jobs market and thus commuting.

The trains are often full and standing off-peak too, especially evenings and peak-hour shoulders. Not helped by some awkward gaps in the timetable, and the 4-car limit to Reigate. Surely this could be mitigated somehow short-term, without the ferocious expense of the East Croydon CARS scheme or Reigate 12-car P3?

 

[Sad Sprinter]

Unless there is significant disruption the Thameslink 12 car 700's provide plenty of capacity up to London Bridge from East Croydon currently. Its the Clapham Jcn/Victoria service that are full and standing off East Croydon and this can be easily fixed by getting everything back upto 12 cars before big infrastructure intervention is needed. If growth continues beyond then infrastructure interventions maybe back on the agenda but the wildcard here is what AI does to the London jobs market and thus commuting.

I was thinking yesterday on my way home it seems Southern has been quite aggressive in keeping train formations largely below 12 coaches.

 

[Surreytraveller]

I was thinking yesterday on my way home it seems Southern has been quite aggressive in keeping train formations largely below 12 coaches.

It's because they've not got much stock since the 313s and 455s went.

 

[TransportHub]

I was thinking yesterday on my way home it seems Southern has been quite aggressive in keeping train formations largely below 12 coaches.

Probably because Southern have ~200 fewer carriages than in 2019

 

[Sad Sprinter]

Probably because Southern have ~200 fewer carriages than in 2019

All over at Southeastern?

 

[PGAT]

All over at Southeastern?

Mostly the loss of the 313s and 455s

 

[cle]

They desperately a new inner stock which is fast doors/dwells, and useful for the Brighton/Coastway locals and South London lines.

377s are a little unwieldy for these - slower doors, tables, toilets... all v nice but unnecessary for short commutes.

 

[JCO1406]

They desperately a new inner stock which is fast doors/dwells, and useful for the Brighton/Coastway locals and South London lines.

377s are a little unwieldy for these - slower doors, tables, toilets... all v nice but unnecessary for short commutes.

Short term, the 458s could work until they get a new fleet fresh out of the factory.

 

[Sad Sprinter]

They desperately a new inner stock which is fast doors/dwells, and useful for the Brighton/Coastway locals and South London lines.

377s are a little unwieldy for these - slower doors, tables, toilets... all v nice but unnecessary for short commutes.

Yes, the table seating looks very weird for these services

 

[rmHawk765]

377s are a little unwieldy for these - slower doors, tables, toilets... all v nice but unnecessary for short commutes.

Absolutely. I think the whole cascading stock thing hasn't gone quite so well for GTR. Neither the 387s nor the 377s are well suited to metro services. And over on the GN side, the 717s are beginning to struggle with pretty considerable overcrowding, only a few years after the rollout was completed. I imagine the same happens on SN.

 

[Sad Sprinter]

Absolutely. I think the whole cascading stock thing hasn't gone quite so well for GTR. Neither the 387s nor the 377s are well suited to metro services. And over on the GN side, the 717s are beginning to struggle with pretty considerable overcrowding, only a few years after the rollout was completed. I imagine the same happens on SN.

I’ve noticed that with the 717s. Not sure what the solution is apart from giving one arm of the Great Northern Electrics over to Thameslink. Even then, you’d probably only be able to squeeze a quarter hourly service from it.

== Doublepost prevention - post automatically merged: 1 May 2026 ==

Mostly the loss of the 313s and 455s

Is this why we’ve got such a weird mish-mash of 387s?

 

[cle]

717s are massively underused from a units POV - and given the max (6 car) is being run, frequency is the only lever - as the stock can't be longer or really changed. Adds the benefit of a 'tube' like service between Ally Pally and Moorgate... (kill the TL calls there)

For Southern, those elements (tables, loos) take up a lot of space on what are packed services - people will routinely stand from Thornton Heath or Sutton into London... should all be 10 car and proper metro stock. Less consideration for luggage either - as they won't usually go to Gatwick.

 

[rmHawk765]

I’ve noticed that with the 717s. Not sure what the solution is apart from giving one arm of the Great Northern Electrics over to Thameslink. Even then, you’d probably only be able to squeeze a quarter hourly service from it.

717s are massively underused from a units POV - and given the max (6 car) is being run, frequency is the only lever - as the stock can't be longer or really changed. Adds the benefit of a 'tube' like service between Ally Pally and Moorgate... (kill the TL calls there)

The only thing that can be done without infrastructure upgrades is to finally deliver the 10tph Hertford peak service that was intended for the 717s. Other than that, it's just platform lengthening, which is pretty difficult in the NCL.
I'm hoping the silly calls at Ally Pally from the Letchworth/Cambridge stoppers will be removed when it becomes 2+4tph off peak in Dec 26. No TL calls there presently though.

For Southern, those elements (tables, loos) take up a lot of space on what are packed services - people will routinely stand from Thornton Heath or Sutton into London... should all be 10 car and proper metro stock. Less consideration for luggage either - as they won't usually go to Gatwick.

As for SN overcrowding, while I'm not too familiar with the hotspots, I'm pretty sure that the Windmill Bridge Jn situation prevents adding any new services via East Croydon (and therefore also hinders our Thameslink services further north!). So it's a very similar situation - except SN doesn't even have the stock to run longer trains.

 

[Zeremony]

They desperately a new inner stock which is fast doors/dwells, and useful for the Brighton/Coastway locals and South London lines.

377s are a little unwieldy for these - slower doors, tables, toilets... all v nice but unnecessary for short commutes.

Wishful thinking, but new rolling stock designed for metro services to property replace the 455s (and 313s I guess) would be ideal and might allow more 377s to cascade to SE.

The Watford services are also crying out to be strengthened from 4/5 cars back to 8.

 

[TransportHub]

There used to be the 2T London Bridge to Coulsdon Town service every half hour through windmill bridge.

The 2B services were 4tph to Sutton all day EWD

And the 1I/2I via Mitcham In was 4tph as far as Epsom

Caterham got a 2Y fast service to Vic in the peaks too


There's definitely paths available in theory, just no stock to run in them

 

[JonathanH]

There used to be the 2T London Bridge to Coulsdon Town service every half hour through windmill bridge.

The 2B services were 4tph to Sutton all day EWD

And the 1I/2I via Mitcham In was 4tph as far as Epsom

Caterham got a 2Y fast service to Vic in the peaks too


There's definitely paths available in theory, just no stock to run in them

The paths aren't necessarily available though, as the removal of some service groups has allowed others to be retimed to be more efficient and increase resilience. In particular, the path previously used by the Coulsdon Town service allows an earlier departure fron London Bridge for the Caterham / Tattenham train, and leaves room for the Peterborough to Horsham train to run on the slow lines from Norwood Junction. Removing trains from the Croydon to Purley corridor helps with punctuality of trains to Redhill.

 

[brad465]

Unless there is significant disruption the Thameslink 12 car 700's provide plenty of capacity up to London Bridge from East Croydon currently. Its the Clapham Jcn/Victoria service that are full and standing off East Croydon and this can be easily fixed by getting everything back upto 12 cars before big infrastructure intervention is needed. If growth continues beyond then infrastructure interventions maybe back on the agenda but the wildcard here is what AI does to the London jobs market and thus commuting.

They desperately a new inner stock which is fast doors/dwells, and useful for the Brighton/Coastway locals and South London lines.

377s are a little unwieldy for these - slower doors, tables, toilets... all v nice but unnecessary for short commutes.

If the 458s going to Southern/GTR report in Modern Railways is to be believed, this would be the best way to get more 12-car BML services; have the 458s on Coastway services, freeing up 377/387s to strengthen mainline diagrams.

 

[TransportHub]

The paths aren't necessarily available though, as the removal of some service groups has allowed others to be retimed to be more efficient and increase resilience. In particular, the path previously used by the Coulsdon Town service allows an earlier departure fron London Bridge for the Caterham / Tattenham train, and leaves room for the Peterborough to Horsham train to run on the slow lines from Norwood Junction. Removing trains from the Croydon to Purley corridor helps with punctuality of trains to Redhill.

Yeah the 'in theory' is doing some heavy lifting there, there is space because the ran before, but that means putting the surrounding trains back to how they were when they ran. If there was the will and stock to reinstate them it could be done

 

[Nicholas Lewis]

If the 458s going to Southern/GTR report in Modern Railways is to be believed, this would be the best way to get more 12-car BML services; have the 458s on Coastway services, freeing up 377/387s to strengthen mainline diagrams.

Given the 5 car 701s seem to have a questionable future on SWR give them to Southern and that will release 30 units to beef up more the Southern main line to 12 cars.

 

[Recessio]

For Southern, those elements (tables, loos) take up a lot of space on what are packed services - people will routinely stand from Thornton Heath or Sutton into London... should all be 10 car and proper metro stock. Less consideration for luggage either - as they won't usually go to Gatwick.

It's getting pretty bad, a few weeks ago I was standing all the way from Cheam! Given up and walk to West Sutton now. Takes longer but guaranteed a seat in the declassified first class area.

 

[SECR 65]

I was wondering could any of the 387s that aren't currently with Southern find their way to BML services? E.g. 350/2s to GWR and remaining 387/1s to SN, or extra stock for GN to bring all of those 387s south of the river?

 

[williamn]

377s are a little unwieldy for these - slower doors, tables, toilets... all v nice but unnecessary for short commutes.

The tables are precisely the reason I take the train over the bus on east coastway routes, enabling me to work.