Thameslink services which have diverted elsewhere..

hash2806 · 14 Jun 2026

Hello all, I hope everyone is well.

I've been wondering for a while now if there have been any Thameslink services which have diverted elsewhere on the GTR network as a result to minimise disruption e.g. a service towards Cambridge (originating from Brighton), diverts to Peterborough for whatever reason.

If I remember correctly, I recall seeing a late night Brighton - Cambridge service being diverted to Peterborough in 2020, however I don't remember the date/month it occurred.

If anyone does know of any cases where this has happened please enlighten me!

Many thanks

RailUK Forums

Andy Orchard · 14 Jun 2026

hash2806 said:
Hello all, I hope everyone is well.

I've been wondering for a while now if there have been any Thameslink services which have diverted elsewhere on the GTR network as a result to minimise disruption e.g. a service towards Cambridge (originating from Brighton), diverts to Peterborough for whatever reason.

If I remember correctly, I recall seeing a late night Brighton - Cambridge service being diverted to Peterborough in 2020, however I don't remember the date/month it occurred.

If anyone does know of any cases where this has happened please enlighten me!

Many thanks

I recall a few years ago when a Horsham to Peterborough service was diverted at St Pancras International to run to Bedford instead due to no driver available to work to Peterborough, hope this helps!

ox_chap · 14 Jun 2026

Well, that's a good question for today (Purley bridge closure). Could, in theory, diversions actually go along lines that Thameslink don't operate? For instance, London Bridge, Dorking, Horsham, Gatwick.

NSE · 14 Jun 2026

ox_chap said:
Well, that's a good question for today (Purley bridge closure). Could, in theory, diversions actually go along lines that Thameslink don't operate? For instance, London Bridge, Dorking, Horsham, Gatwick.

In theory yes, but you’d need to make sure 700’s are cleared for the route. As they operate down many 377 cleared routes (East Grinstead, the Brighton Mainline, plus they previously went to Littlehampton via the West Coastway, used to divert via Lewes and have visited Eastbourne during testing), it’s highly likely they would fit down via Dorking, but I don’t believe they’ve been officially cleared south of Sutton (happy to stand corrected). You’d then need a Southern driver to conduct the train as no driver would sign it at TL. So yes, it’s all possible but would take a lot of planning and execution.

The reason Southern can do it ‘on the fly’ so to speak, is because they have drivers that sign the route and the stock and so they can essentially create an ad hoc service running London - Dorking - Horsham - Gatwick, even if they change drivers at Horsham if they can’t get one driver to do the whole journey. TL don’t have any, so it would become very difficult.

Peter Mugridge · 14 Jun 2026

I'm pretty sure they did run a few 700s through Epsom prior to service introduction - didn't they do some of their pre-service testing between Dorking and Horsham?

...or has my memory completely fused out?

devon_belle · 14 Jun 2026

I've seen references on this forum to TL 700s going down via Epsom and Dorking. Supposedly it has happened in service during disruption when a driver has recently transferred from Southern to Thameslink.

I have seen no evidence to support these claims though. Would love to see a pic if anyone has one.

== Doublepost prevention - post automatically merged: 14 Jun 2026 ==

During disruption this weekend Thameslink were running into the LC&DR side of London Victoria. Not sure if that meets your criteria.

I saw a 700 entering Victoria on an ECS run a few weeks ago, much to my surprise having never seen it before.

MrJeeves · 14 Jun 2026

devon_belle said:
I saw a 700 entering Victoria on an ECS run a few weeks ago, much to my surprise having never seen it before.

There are a number of booked Thameslink workings to and from Victoria in the early/late hours most weeks.

In fact, today (and a number of future weekends) there is an hourly Victoria-Sevenoaks Thameslink service!

devon_belle · 14 Jun 2026

MrJeeves said:
There are a number of booked Thameslink workings to and from Victoria in the early/late hours most weeks.

In fact, today (and a number of future weekends) there is an hourly Victoria-Sevenoaks Thameslink service!

The more you know!

SECR 65 · 15 Jun 2026

Are there any drivers who sign both 700 and 377?

MrJeeves · 15 Jun 2026

SECR 65 said:
Are there any drivers who sign both 700 and 377?

As I understand it, this would only be a driver who had recently transferred from one side of the business to the other. I don't believe anyone is trained on both at once (except potentially some instructors/trainers?).

JonathanH · 15 Jun 2026

The extremely interesting maps of route knowledge referenced in this thread https://www.railforums.co.uk/thread....uk/threads/gtr-diagrams.302870/#post-7822591 explain why diverting to alternative destinations is uncommon.

Of note is that West Croydon appears to be signed by a number of 'mainline' drivers.

The afforementioned route from Sutton to Horsham is not known by any Thameslink drivers.

NSE · 15 Jun 2026

MrJeeves said:
As I understand it, this would only be a driver who had recently transferred from one side of the business to the other. I don't believe anyone is trained on both at once (except potentially some instructors/trainers?).

There are people that sign both 377’s and 700’s, but all the ones I know of are of the trainer/instructor grade and so using them to help in times like this is easier said then done.

devon_belle said:
I've seen references on this forum to TL 700s going down via Epsom and Dorking. Supposedly it has happened in service during disruption when a driver has recently transferred from Southern to Thameslink.

I have seen no evidence to support these claims though. Would love to see a pic if anyone has one.

I’d be very surprised to know 700’s have gone down via Epsom and Dorking with drivers that have recently ‘gone across’. Mostly because that hasn’t happened for a while. Drivers did go across when TL opened depots at places like Horsham when the core expanded to cover the ECML, but drivers don’t transfer virtually at all now that the depots are set up.

Additionally I don’t think it would be possible as Cricklewood drivers generally take most of the Sutton Loop work and so wouldn’t be diagrammed to take a train to Horsham and thus wouldn’t be faced with the option of taking a Horsham via Epsom and Dorking (and wouldn’t sign the routes).

devon_belle · 16 Jun 2026

I found the thread: https://www.railforums.co.uk/thread...eterborough-25-05-via-dorking-tonight.252149/

My memory wasn't spot on, sounds like Thameslink drivers may have been route conducted over the Dorking line but posters assert that it has happened.

RichJF · 16 Jun 2026

Yes. I got on the 9L03 St Pancras to East Grinstead Thameslink on the morning of 3rd June. There was a train failure/fault on the East Grinstead line, so it arrived into P3 at East Croydon & ran fast to Gatwick. The driver didn't change the in carriage displays so we got a rapid South Croydon, Sanderstead, Oxted then it gave up as we smashed Salfords.

Other TL's were cancelled & Southerns heavily delayed.

Express380 · 16 Jun 2026

Peter Mugridge said:
I'm pretty sure they did run a few 700s through Epsom prior to service introduction - didn't they do some of their pre-service testing between Dorking and Horsham?

...or has my memory completely fused out?

I jumped off a 700 at Horsham a while back and the return service was cancelled, it then went ECS via Dorking having followed it Traksy.

MrJeeves · 16 Jun 2026

Express380 said:
I jumped off a 700 at Horsham a while back

Do you know/can you work out when?

Express380 · 16 Jun 2026

== Doublepost prevention - post automatically merged: 16 Jun 2026 ==

MrJeeves said:
Do you know/can you work out when?

It was either 29th March 2024 around 6-7pm or 18th Sep 2025 around 2ish but I think it was the former.

philjo · 16 Jun 2026

When there is disruption on the ECML some northbound Cambridge services have been diverted at short notice to terminate at West Hampstead.
Some northbound Peterborough services have occasionally been diverted to terminate at Letchworth.

bramling · 16 Jun 2026

hash2806 said:
Hello all, I hope everyone is well.

I've been wondering for a while now if there have been any Thameslink services which have diverted elsewhere on the GTR network as a result to minimise disruption e.g. a service towards Cambridge (originating from Brighton), diverts to Peterborough for whatever reason.

If I remember correctly, I recall seeing a late night Brighton - Cambridge service being diverted to Peterborough in 2020, however I don't remember the date/month it occurred.

If anyone does know of any cases where this has happened please enlighten me!

Many thanks

IME it’s pretty much unheard of for a Cambridge service to go to Peterborough, or vice versa, once past Finsbury Park. One presumes there will have been occasions where a train turns up at Finsbury Park to have no relief, and ends up being made into something going somewhere else if a driver is available, but more likely to end up going into Hornsey.

Unfortunately what tends to happen on the GN side is if a Peterborough service can’t get to Peterborough then it either just sits blocking the line somewhere, or on some occasions it may go to Letchworth and then either sit there in the reception roads, or return to London. Same with Cambridge services. There aren’t any convenient 12-car boltholes between Finsbury Park and Peterborough/Cambridge, and then there’s the whole issue of GTR’s compartmentalised route knowledge.

A S Leib · 16 Jun 2026

Has a Sutton service ever been diverted the other way around the loop than it was originally booked to go?

Hadders · 16 Jun 2026

We were told at the time, by someone apparently in the know, was that when there was disruption in the core diversion of services on the GN side into and out of Kings Cross would be 'simple'.

It does happen sometimes, but not frequently in my experience.

galwhv69 · 16 Jun 2026

A S Leib said:
Has a Sutton service ever been diverted the other way around the loop than it was originally booked to go?

Yes does happen every now and again

Andrew S · 16 Jun 2026

If anything goes wrong on the Woolwich line it's fairly normal to divert the Rainham TL trains via Bexleyheath and Lewisham.

Bald Rick · 16 Jun 2026

A S Leib said:
Has a Sutton service ever been diverted the other way around the loop than it was originally booked to go?

Routinely, typically because of a fault with infrastructure or train that blocks only one way round. It’s quite a handy contingency, as all else being equal it will be in the right path once it is back at Streatham, making recovery straightforward.

That has given me a thought though, and that is whether it counts as a cancellation or not. To paraphrase the late great Eric Morecambe, it serves all the right stations, just not necessarily in the right order!

bramling · 16 Jun 2026

Hadders said:
We were told at the time, by someone apparently in the know, was that when there was disruption in the core diversion of services on the GN side into and out of Kings Cross would be 'simple'.

That has to be the biggest joke going, as we both knew at the time.

I guess it is quite “simple” just to sit trains down on the running line and wait for the disruption to be over, which is what often seems to happen. This is no doubt one of several reasons why incidents tend to result in the shutters being pulled down on any attempt to provide a usable service.

Mattplans · 30 Jun 2026

9L91 has today been diverted from East Grinstead to Gatwick Airport

15:59 Bedford to East Grinstead | RailChecker Web

Check train times, formations, crowding, planning, disruption and more on RailChecker.

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Thameslink services which have diverted elsewhere..

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