Regular Thameslink disruption: what could be done to improve performance and resilience?

[Magdalia]

There's very little revenue driver that says Brighton is a better pairing for Bedford than another destination

There is the data. After Cambridge the next biggest Thameslink flows for Brighton-East of England are St Albans, Bedford and Luton.

I have identified the following South East-East of England flows bigger than 10k one way journeys:


26884 Brighton-Cambridge

22222 Brighton-St Albans
17119 Brighton-Bedford

13679 Brighton-Luton Airport Parkway

12896 Brighton-Luton

All of Harpenden, Leagrave and Flitwick also are more than 5000 journeys with Brighton.

The current 30-minute patterns create 10/20 service intervals everywhere

Actually it doesn't. Cambridge-Brighton and Peterborough-Horsham are 15 minutes apart all the way between Hitchin and East Croydon. The Bedford trains are at 15 minute intervals on the Midland Main Line, then shift to 18/12 through the core by alternate trains calling at West Hampstead. St Albans-Sutton is at 15 minute intervals all the way to Streatham.

It doesn't take a mathematical genius to work out, that to have consistent 15-minute patterns north and south of the river every 4tph service north of the river needs to be paired with the same 4tph service south of the river.

But maybe it does take a genius to spot that the Quarry and Redhill trains depart East Croydon at roughly the same time going south, while the Quarry and Redhill trains arrive East Croydon at roughly the same time going north, enabling the 15 minute pattern to be preserved.

Having driver pools that cover a substantial service group wouldn't be costly if that service group is high-frequency and low geographic coverage. Cambridge and Peterborough plus Brighton and Horsham would be expensive; Cambridge and Peterborough plus just Brighton would be very reasonable.

The difference would be small: Three Bridges-Horsham is less than 10 miles. And that would vanish if a way could be found of terminating the Peterborough trains at Three Bridges.

 

[NCT]

Actually it doesn't. Cambridge-Brighton and Peterborough-Horsham are 15 minutes apart all the way between Hitchin and East Croydon. The Bedford trains are at 15 minute intervals on the Midland Main Line, then shift to 18/12 through the core by alternate trains calling at West Hampstead. St Albans-Sutton is at 15 minute intervals all the way to Streatham.

But maybe it does take a genius to spot that the Quarry and Redhill trains depart East Croydon at roughly the same time going south, while the Quarry and Redhill trains arrive East Croydon at roughly the same time going north, enabling the 15 minute pattern to be preserved.

Very well, every-half-where. All the 15-minute patterns you've identified are north of the river; and south-of-the-river routes (with the exception of Herne Hill) are 10/20, by virtue of being fed by different routes. Your example of relying on two routes to form combined 15-minute patterns proves my point.

 

[London Trains]

Very well, every-half-where. All the 15-minute patterns you've identified are north of the river; and south-of-the-river routes (with the exception of Herne Hill) are 10/20, by virtue of being fed by different routes. Your example of relying on two routes to form combined 15-minute patterns proves my point.

But there's a good reason it is that way - it allows an even 6tph pattern down the Redhill line in conjunction with the Victoria to Reigate service. Unless the paths and money can be found for 8tph, it needs to stay this way.

Where I do think an improvement can be made though is to get rid of the inconsistent skip-stopping down the Redhill line between East Croydon and Gatwick - i.e. most services, if not all services should stop at all stops between Purley and Horley (inclusive).

 

[Magdalia]

Very well, every-half-where. All the 15-minute patterns you've identified are north of the river; and south-of-the-river routes (with the exception of Herne Hill) are 10/20, by virtue of being fed by different routes. Your example of relying on two routes to form combined 15-minute patterns proves my point.

What it proves is that the 10/20 intervals south of the river are not caused by Thameslink, they are Southern timetabling issues.

But there's a good reason it is that way - it allows an even 6tph pattern down the Redhill line in conjunction with the Victoria to Reigate service. Unless the paths and money can be found for 8tph, it needs to stay this way.

 

[NCT]

There is the data. After Cambridge the next biggest Thameslink flows for Brighton-East of England are St Albans, Bedford and Luton.

All of Harpenden, Leagrave and Flitwick also are more than 5000 journeys with Brighton.

The numbers are bit closer than I previously thought. That said, those 20k flows pale in comparison with ~2.5 million to London BR. A well performing smaller service group would have a bigger impact on the London BR demand than imposing a same-platform interchange on those 5-20k cross-London flows.

What is more, the current complex pairing means that Brighton to Stevenage only has a 2tph opportunity to travel. Timetable asymmetry also means in the other direction it's St Albans - Brighton that's limited to 2tph.

A consistent north-south pairing and sorting the timetable symmetry (which gets far easier with a simpler service pattern) means everybody gets a consistent 4tph opportunity to travel. This turns a large collection of cross-London journeys from timetable journeys to metro journeys, and I posit that the revenue improvement from metroisation more than compensates for the loss of some direct journeys.


== Doublepost prevention - post automatically merged: 27 Dec 2025 ==

But there's a good reason it is that way - it allows an even 6tph pattern down the Redhill line in conjunction with the Victoria to Reigate service. Unless the paths and money can be found for 8tph, it needs to stay this way.

Where I do think an improvement can be made though is to get rid of the inconsistent skip-stopping down the Redhill line between East Croydon and Gatwick - i.e. most services, if not all services should stop at all stops between Purley and Horley (inclusive).

Except those services are not every 10 minutes at East Croydon. With different stopping patterns a 10-minute frequency at one end is pretty meaningless - i.e. the Victoria service does not allow give you a 10-minute effective frequency between Redhill and London Bridge.

 

[London Trains]

Except those services are not every 10 minutes at East Croydon. With different stopping patterns a 10-minute frequency at one end is pretty meaningless - i.e. the Victoria service does not allow give you a 10-minute effective frequency between Redhill and London Bridge.

They are southbound though - the solution to fix the northbound services would be to swap the timings of the East Grinstead and Reigate services, though I haven't checked whether this conflicts with GWR services.

As I said in my post before, I do think the stopping patterns along the Redhill line need to be simplified, preferably everything would stop everywhere. I would also aim to remove any interactions between the Quarry (fast) and Redhill (slow) lines between Windmill Bridge Junction and just north of Gatwick - the only service which still crosses over between the two locations is the northbound Horsham to Peterborough service.

 

[JonathanH]

As I said in my post, I do think the stopping patterns along the Redhill line need to be simplified, preferably everything would stop everywhere. I would also aim to remove any interaction between the Quarry and Redhill lines between Windmill Bridge Junction and Gatwick - the only service which still crosses over between the two is the northbound Horsham to Peterborough service.

Yes, it is a bit unfortunate (for Quarry Line users) that the Horsham to Peterborough service doesn't have a path on the slow northbound, because of the conflict with the Caterham / Tattenham service and the East Grinstead to Victoria train, but I don't think it can really be avoided.

However, for Redhill passengers, the skip stopping results in faster services than would be available if everything stopped at Purley, Coulsdon South and Merstham. Which users are you hoping would benefit from Redhill having only stopping services? Does that accurately reflect passenger demand?

Northbound, off-peak, the Reigate train often connects with the northbound Cambridge at East Croydon if a passenger is sat in the right place for the stairs.

Redhill departures northbound, at xx10, xx18 and xx29 aren't a bad spread. Southbound, it is basically xx00, xx07, xx21, xx30, xx35, xx51 from London Bridge to Redhill.

 

[Nicholas Lewis]

I can't remember the details of why the Cats and Tats got left out of Thameslink in 2018 (and we got Rainham instead), but, if the planners didn't think it would work before the experience of the last 7 years, they sure aren't going to think its workable now, and still without CARS.

== Doublepost prevention - post automatically merged: 27 Dec 2025 ==

Too many conflicts at Windmill Bridge Jcn.

CARS was a pipe dream even before Covid the 12 car 700's provided a massive boost in capacity and always understated is their ability to hoover up 1000 people very rapidly.

I hope that 24tph has been quietly buried in the grave next to Cambridge-Maidstone. 20tph should be the limit to give firebreaks in the peak timetable. I do agree that having driver pools that cover more services would help, though it will be costly. In FCC days Cambridge drivers always worked to Peterborough, and vice versa, and the loss of that flexibility has been damaging.

Probably correct but why specify 24TpH in the first place with all the extra costs associated with that spec.

 

[London Trains]

However, for Redhill passengers, the skip stopping results in faster services than would be available if everything stopped at Purley, Coulsdon South and Merstham. Which users are you hoping would benefit from Redhill having only stopping services? Does that accurately reflect passenger demand?

I understand my suggestion isn't ideal for Redhill passengers, but a couple of minutes added to journey times really isn't the end of the world - on the other hand, it would be revolutionary for users of Purley, Coulsdon South, Merstham, Earlswood and Salfords though, as it is a trade off of services taking a couple of minutes longer for a 33% increase in services at Purley, a 50% increase in services at Coulsdon South and Merstham, and an 100% increase in services at Earlswood and Salfords, and it massively improves connections between intermediate stations.

 

[NCT]

I can see the attraction of Horley, Salfords and Earleswood getting 4tph, on the assumption that most Horsham and Crawley passengers would change at Three Bridges for a faster journey via the Quarry Lines. I do think however that upon doors closing at Redhill all those passengers would want a fast journey into London. I don't think Merstham and Coulsdon South warrant 6tph - I think the Thameslink can skip stop with the Victoria acting as the all-stations collector / local connector. Purley has the Cats and Tats so don't need all the Redhill trains to call either. And I do think the Redhill Thameslink need to cross at Stoats Nest - staying on the Slows means a painful crawl through Purley Oaks and South Croydon.

 

[izvor]

I can see the attraction of Horley, Salfords and Earleswood getting 4tph, on the assumption that most Horsham and Crawley passengers would change at Three Bridges for a faster journey via the Quarry Lines. I do think however that upon doors closing at Redhill all those passengers would want a fast journey into London. I don't think Merstham and Coulsdon South warrant 6tph - I think the Thameslink can skip stop with the Victoria acting as the all-stations collector / local connector. Purley has the Cats and Tats so don't need all the Redhill trains to call either. And I do think the Redhill Thameslink need to cross at Stoats Nest - staying on the Slows means a painful crawl through Purley Oaks and South Croydon.

Horley does get 4tph now, though it lost its hourly fast Victoria with covid - for an expanding town surely this would justify restoration, particularly with Thameslink so unreliable.

Salfords and Earlswood I would find hard to justify doubling to 4tph with consequent slowing for outer passengers. Likewise, as you say, I don't think Merstham and Coulsdon South warrant 6tph. Redhill (and Horley) has already suffered with extended journey times to London - particularly Victoria - with its "metroisation", the quid-pro-quo for increase to 6tph which is welcome of course.

 

[westcoaster]

At the north end the Luton drivers who sign Rainham don't sign the Catford loop (and neither do the Gillingham Thameslink drivers).

This is incorrect Luton drivers sign Blackfriars to Sevenoaks and Orpington both via Catford and via Herne Hill ( and Orpington to sevenoaks).
Half of Cricklewood depot sign Blackfriars to Orpington both ways.
Ashford drivers sign Sevenoaks/Orpington to Blackfriars both ways plus now up onto the GN side.
Welyn drivers sign Sevenoaks/Orpington both ways

So there is a big pool of drivers who the Catford loop.

 

[Nicholas Lewis]

I understand my suggestion isn't ideal for Redhill passengers, but a couple of minutes added to journey times really isn't the end of the world - on the other hand, it would be revolutionary for users of Purley, Coulsdon South, Merstham, Earlswood and Salfords though, as it is a trade off of services taking a couple of minutes longer for a 33% increase in services at Purley, a 50% increase in services at Coulsdon South and Merstham, and an 100% increase in services at Earlswood and Salfords, and it massively improves connections between intermediate stations.

The service pattern on Redhills is fine its what happens when there's perturbation thats the issue.

So if Bedford-3B's affected add stop orders to Peterbough-Horshams at Earlswood & Salfords . If Peterborough-Horshams impacted add stop orders to Bedford-3B's at Coulsdon Sth & Merstham.

If core blocked run 2tph Horsham- London Bridge all stations via Redhill. Yes there are platform implications at London Bridge Central but 15 isn't used most of the day and 10 is only occupied 15m every hour so they could be accommodated.

If only the above were implemented as a matter of course a half decent service would be maintained on the Redhills.

 

[NorthKent1989]

One of the may things I see on Thameslink threads is the dissatisfaction with the Peterborough service on the north side and the Rainham service on the south side, Peterborough seems to far out while Rainham is outer suburban but has too many stations, both have a problem with reliability both previously had faster services along their respective corridors, it does make one wonder if at what point they’ll have to rejig Thameslink again in the future as nothing seems to have improved and it’s been nearly eight years since the big timetable change of 2018.

I don’t know enough about passenger services on the Peterborough end prior to 2018, while I have laid out my own experiences with the Rainham service and its many faults enough times but can someone explain to me what the service levels were on the Peterborough service before the Thameslink takeover?

Is there the same level of dissatisfaction on the Cambridge services

 

[bramling]

One of the may things I see on Thameslink threads is the dissatisfaction with the Peterborough service on the north side and the Rainham service on the south side, Peterborough seems to far out while Rainham is outer suburban but has too many stations, both have a problem with reliability both previously had faster services along their respective corridors, it does make one wonder if at what point they’ll have to rejig Thameslink again in the future as nothing seems to have improved and it’s been nearly eight years since the big timetable change of 2018.

I don’t know enough about passenger services on the Peterborough end prior to 2018, while I have laid out my own experiences with the Rainham service and its many faults enough times but can someone explain to me what the service levels were on the Peterborough service before the Thameslink takeover?

Is there the same level of dissatisfaction on the Cambridge services

Peterborough was previously 2tph, made up of 1tph KX Finsbury Park Stevenage then all stations, and 1tph KX Finsbury Park Potters Bar Hatfield then all stations. At peak hours this changed to 2tph with the faster service pattern.

On top of that there was generally 2tph additional in the peaks generally fast to either Biggleswade or St Neots, with some Stevenage calls as well. Then continued hourly from the end of the evening peak until close of traffic, with the stopping service diverted to Letchworth instead.

Sunday was 1tph, with a handful of tidal extras fast to/from Biggleswade or St Neots.

The Cambridge route isn’t overly happy with Thameslink either. Firstly Cambridge-Brighton isn’t overly dependable and tends to be the first service to disappear during disruption. Secondly as they have the same issues in terms of disruption spreading and poor recovery. But unlike Peterborough the Cambridge route does at least have other services, albeit probably meaning a slower journey time.

 

[ScotGG]

Yep Cambridge is poor in my experience but at least there's Great Northern or Greater Anglia to get to London at reasonable frequencies (off peak at least it's normally ok).

Perhaps it'll take GBR becoming established for some changes across Thameslink and boy are they needed.

 

[Magdalia]

Is there the same level of dissatisfaction on the Cambridge services

The Cambridge route isn’t overly happy with Thameslink either. Firstly Cambridge-Brighton isn’t overly dependable and tends to be the first service to disappear during disruption. Secondly as they have the same issues in terms of disruption spreading and poor recovery. But unlike Peterborough the Cambridge route does at least have other services, albeit probably meaning a slower journey time.

Cambridge itself has other options, both the fast trains to/from the Fens, and the Liverpool Street line.

The intermediate stations are more exposed, though they were spared the worst when Cambridge-Maidstone failed to materialise.

Peterborough was previously 2tph, made up of 1tph KX Finsbury Park Stevenage then all stations, and 1tph KX Finsbury Park Potters Bar Hatfield then all stations. At peak hours this changed to 2tph with the faster service pattern.

Prior to 2018 the intermediate stations between Hitchin and Cambridge had the same off peak service as the Peterborough line. In the peaks the Cambridge line got all of the slow trains, plus peak hour semifasts mostly to/from Royston, and the Fen Line trains having stops at Letchworth and Royston.

I do wonder whether it would be possible off peak to go back to something like what existed before 2018, with the Kings Cross stoppers alternating between Cambridge and Peterborough and the Horsham trains alternating between Peterborough and Letchworth. A possible drawback is that I suspect that it is only a matter of time before the stopping service will need to run through to Cambridge all day.

 

[JonathanH]

Redhill (and Horley) has already suffered with extended journey times to London - particularly Victoria - with its "metroisation", the quid-pro-quo for increase to 6tph which is welcome of course.

Redhill had 6tph to London before 2018 (right back to 2008). Indeed, it also had 6tph at the turn of the century when Southeastern and Thameslink had hourly calls. The current timetable is a good compromise for journey times to London and local journeys for all of the Redhill branch stations.

I do wonder whether it would be possible off peak to go back to something like what existed before 2018, with the Kings Cross stoppers alternating between Cambridge and Peterborough and the Horsham trains alternating between Peterborough and Letchworth.

I think there is an 8-car / 12-car issue with that idea, both for capacity on the Peterborough line, the use of Kings Cross, and the small stations to Cambridge.

 

[bramling]

I do wonder whether it would be possible off peak to go back to something like what existed before 2018, with the Kings Cross stoppers alternating between Cambridge and Peterborough and the Horsham trains alternating between Peterborough and Letchworth. A possible drawback is that I suspect that it is only a matter of time before the stopping service will need to run through to Cambridge all day.

I don't think the off-peak terminating at Letchworth is a major issue, if anything it delivers a slight benefit as it's one less train to get tangled up with, and at the times when trains reverse at Letchworth 3tph Letchworth to Cambridge (not including the fasts) seems more than adequate, and they never seem to be heavily loaded.

Horsham-Letchworth would probably help a bit, but its kind of tacking the symptom not the cause.

 

[izvor]

Redhill had 6tph to London before 2018 (right back to 2008).

You are right of course. They are better spaced now - perhaps that's what I was thinking about.

The current timetable is a good compromise for journey times to London and local journeys for all of the Redhill branch stations.

It is. On a good day!

Are there any plans for the 4-car Reigate-Vics, now that Reigate P3 is not likely to happen?