2024 Tube Stock (Siemens Inspiro London)

[CarrotPie]

The S stock rollout was arguably quicker, but many forget that all the S8s had to go back to Derby twice for modifications, leading to up to three S7+1s being in service (with a protracted roll out for the S7s too). Some of that was down to signalling upgrades changing scope, but not all.

So they had to go back to Derby for modifications twice and their rollout was still quicker than the 24TS? That's interesting.

First delivery as 7-car 21/10/2009.
first S8 entered service 31/7/2010

Hmm, 9 months from first delivery to first train in service. The first 24TS has already been in London more than 9 months, and it's still going to be another year or so until the first train enters service. Deary me...

 

[Thirteen]

I know some people on here would risk passenger's safety by having new trains out ASAP but there is a reason things are tested.

 

[CarrotPie]

I know some people on here would risk passenger's safety by having new trains out ASAP but there is a reason things are tested.

That's unfair. I think everyone here knows why new stock is tested - both for safety-critical and non-safety-critical reasons - and I don't see a problem with that. Most new trains take half a year, a year, maybe slightly longer, to test (depending on their complexity); the S Stock took 9 months, for example. But the first 24TS to arrive in London did so about 16 months ago, and it's still going to be at least another 9 until it enters service, probably longer.

I know that some of this is due to the infrastructure, not the trains, but then that can't be blamed on Siemens, unless they delivered non-compliant trains, which seems unlikely (and it would not be in their interests to do so!).

TL;DR: we understand new trains need testing, but it's going to be 2-2.5 years from first delivery to entering service, which is a lot longer than other new trains (except the 701s, but same point stands there).

 

[sh24]

My layman's impression is the 24TS incorporates a lot more innovation than the S stock. Innovation means complexity, unfamiliarity and lots of things going wrong so this isn't a huge surprise.

 

[Snow1964]

That's unfair. I think everyone here knows why new stock is tested - both for safety-critical and non-safety-critical reasons - and I don't see a problem with that. Most new trains take half a year, a year, maybe slightly longer, to test (depending on their complexity); the S Stock took 9 months, for example. But the first 24TS to arrive in London did so about 16 months ago, and it's still going to be at least another 9 until it enters service, probably longer.

The first completed train went from Vienna to Wildenrath test track in August 2023, so one train is already over 2.5 years old.

It is now looking like the testing phase will take another 9-16 months, so that will mean testing will have taken around 3.5 - 4 years.

Whichever way you look at it, that doesn't suggest every London Underground manager and Piccadilly line employee and contractor is going all out every hour of the week to expedite the introduction. Taking 32,000 hours to test is closer to glacial pace than getting it done as fast as possible.

 

[35B]

The first completed train went from Vienna to Wildenrath test track in August 2023, so one train is already over 2.5 years old.

It is now looking like the testing phase will take another 9-16 months, so that will mean testing will have taken around 3.5 - 4 years.

Whichever way you look at it, that doesn't suggest every London Underground manager and Piccadilly line employee and contractor is going all out every hour of the week to expedite the introduction. Taking 32,000 hours to test is closer to glacial pace than getting it done as fast as possible.

32000 hours is about 18 person years. Defining that as "glacial" confuses the amount of work with the difficulty of what's required, and also makes assumptions about what level of progress is possible.

 

[jumble]

The first completed train went from Vienna to Wildenrath test track in August 2023, so one train is already over 2.5 years old.

It is now looking like the testing phase will take another 9-16 months, so that will mean testing will have taken around 3.5 - 4 years.

Whichever way you look at it, that doesn't suggest every London Underground manager and Piccadilly line employee and contractor is going all out every hour of the week to expedite the introduction. Taking 32,000 hours to test is closer to glacial pace than getting it done as fast as possible.

Are you suggesting that LU close the Piccadilly line completely and do nothing except testing and don't wait for any necessary infrastructure changes or re work to take place?
I am sure you realise that after either further testing is needed.

 

[Snow1964]

Are you suggesting that LU close the Piccadilly line completely and do nothing except testing and don't wait for any necessary infrastructure changes or re work to take place?
I am sure you realise that after either further testing is needed.

No, that is taking it out of context, the Piccadilly line train order was June 2018 (almost 8 years ago).

So have had 7.7 years to do infrastructure changes (but lets be fair and take off 1.5 years for pandemic shutdowns), so still have had over 6 years to alter the infrastructure.

Now if testing reveals further changes needed, that's ok, but unless someone seriously screwed up the specs and design, would expect just minor tweaks (to optimise) as we approach the start of year 9, not anything major/significant remaining in testing and certification process.

 

[CarrotPie]

No, that is taking it out of context, the Piccadilly line train order was June 2018 (almost 8 years ago).

So have had 7.7 years to do infrastructure changes (but lets be fair and take off 1.5 years for pandemic shutdowns), so still have had over 6 years to alter the infrastructure.

Now if testing reveals further changes needed, that's ok, but unless someone seriously screwed up the specs and design, would expect just minor tweaks (to optimise) as we approach the start of year 9, not anything major/significant remaining in testing and certification process.

And they've also had a train for over a year already, so they (should) have had ample time to go "oops, we might need to move that signal/bridge/platform/wall".

32000 hours is about 18 person years. Defining that as "glacial" confuses the amount of work with the difficulty of what's required, and also makes assumptions about what level of progress is possible.

The S Stock took 9 months; the 24TS is going to take a couple of years. Are you saying that the 24TS is 4 times as innovative as the S Stock?

Are you suggesting that LU close the Piccadilly line completely and do nothing except testing and don't wait for any necessary infrastructure changes or re work to take place?
I am sure you realise that after either further testing is needed.

Eh?

== Doublepost prevention - post automatically merged: 3 Mar 2026 ==

Oh, and doesn't the Piccadilly line (or, rather, bits of it) keep closing for 24TS testing lately, anyway?

 

[Mikey C]

A different project, but starting to feel like the slightly shambolic delays to the Elizabeth Line, which only started being announced 4 months before the planned opening date, and from then on further delays kept on being announced.

 

[GFE]

Tfl really do seem to have struggled with the infrastructure works and the associated contracting mechanisms. The scope of the track quality & clearance works continues to be "Defined" following experience with the novelties of the train. Similar with the depot modifications to perform the maintenance tasks ( which are now clearer). The platform interface CCTV installation work seems trickier/poorly resourced. So these infrastructure works are using many of the weekend closures that were previously earmarked for train testing.
Thus train testing has been delayed

 

[BRX]

I’m sorry did I just read they need nearly half a billion pounds additional funding. Did I really that correctly.

Half a billion pounds

It's less dramatic when you consider it's about £60 per Londoner.

 

[eastwestdivide]

Just saw 2024 stock on the move today, Goole to Old Dalby:

Realtime Trains | 6X22 0943 Goole Glassworks Gbrf to Old Dalby | 31/03/2026

Real-time train running information for 6X22 0943 departure from Goole Glassworks Gbrf to Old Dalby on 31/03/2026. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

With cars ending -75 between wagons and a 66 each end (66774, 66790).

Snapped at Rotherham:

 

[Mr. SW]

Damn! I missed it by a whisker coming through Loughborough!

 

[yorkshirerail]

Interestingly a set has been taken to Gascogine wood today. Wonder if this will become a regular storage place for them.

 

[Pakenhamtrain]

Are you suggesting that LU close the Piccadilly line completely and do nothing except testing and don't wait for any necessary infrastructure changes or re work to take place?
I am sure you realise that after either further testing is needed.

Do they do weekday overnight closures?

Down here the Werribee line has been closed nightly from 2030 until last train basically for a year to allow X'trapolis 2.0 testing. It wasn't until around a couple months ago they allowed them to run around with other trains for testing. I I believe the first unit is in service soon.

A different project, but starting to feel like the slightly shambolic delays to the Elizabeth Line, which only started being announced 4 months before the planned opening date, and from then on further delays kept on being announced.

The metro tunnel team down here took great learnings from all the errors.

 

[xtmw]

Do they do weekday overnight closures?

A variety of works can take place during engineering hours. Such as track replacement, rail grinding, welding track etc. Unfortunately only so much can be done during the limited window and therefore weekend closures are necessary.

I believe all work must be completed by around 0400 otherwise you'd risk the service starting up later than it should, and more importantly the safety of P Way/trackside staff. District Dave tells a good tale of late surrender here!

Currently there are overnight closures on the Northern line (Bank Branch), with no service after 2200, this is due to track replacement. So yes, overnight closures do happen but much work happens during engineering hours/weekend possessions. There are occasionally weekday closures, but these are kept to a minimum. The last weekday closure that comes to mind was for signalling works on the Central Line.

 

[Mawkie]

Took a snap of Cockfosters depot today, still the same two 24 Stocks lurking.

(Picture shows two 24 stock trains and a 73 in the background, all stabled in Cockfosters depot.)

When are more coming? I had a good laugh last week in the mess room as the latest rumour is that the delay to the 24 Stocks entering service, combined with apparent very high storage fees charged by Siemens mean that LU is looking for places to store the trains as they are delivered.

The best one I heard was closing the T4 Loop and storing 60 trains end to end! Hopefully just a rumour...

 

[Gag Halfrunt]

On a serious note, could some heritage railways earn some money by renting out empty sidings? Or will the 24TS take up the space vacated by Class 701s at Long Marston?

 

[Nym]

On a serious note, could some heritage railways earn some money by renting out empty sidings? Or will the 24TS take up the space vacated by Class 701s at Long Marston?

Long Marston costs money and isn't exactly flush with space at the moment.
Heritage Railways would need to be sufficiently secured, which there just isn't much space for, especially such a long set that you can't realistically deliver by road, so can't really serve this purpose.

There is of course the "Global Centre of Rail Excellence" which was supposed to be built out with warm secure storage by now. How's that going?

The thing is, closing the T4 loop and using it to store units isn't actually the worst idea I've heard on this.

Also, good on Siemens for actually holding TfL to account on what appears to be their contract terms. Feels like TfL may be getting a taste of their own medicine here.

EDIT:
One also needs to consider powering the units while stabled to prevent there being issues when coming out of store. 630V / 750V double pole shore supplies aren't the easiest thing in the world to find.

Double Edit:

Wonder if there's any regret of not taking forwards the plans for a secondary depot at Ruislip for commissioning these new fleets. I would doubt it since most of the team that envisaged this approach have left, been pushed out or retired.

 

[Snow1964]

On a serious note, could some heritage railways earn some money by renting out empty sidings? Or will the 24TS take up the space vacated by Class 701s at Long Marston?

Is the Aldwych branch still connected (even if mothballed), if so could probably store handful of trains there end to end.

If I remember correctly the Jubilee line Charing Cross branch had some fairly long overrun tunnels, and probably don't need both platforms retained available, so probably park couple of trains there too. And if they could make do without it as a reversing location (there is a trailing crossover between Waterloo and Southwark which might be alternative) could get about dozen trains stored there

 

[xtmw]

The line no longer has live traction current, and this has been the state since 2023. There is no longer the appropriate signalling to allow train movements into the Aldwych branch.

I guess 24 stocks could be towed via battery locos but it seems unlikely as the points themselves haven't actually been plain lined, although if you ask me it's too much hassle... As said above a way to keep the units "on" whilst stabled needs to be founds - which makes stabling on the Aldwych branch even more unlikely

(there is a trailing crossover between Waterloo and Southwark which might be alternative) could get about dozen trains stored there

Is there? I was under the impression the crossover on the Jubilee line was between Westminster and Waterloo, with NB trains reversing just ahead of the station then heading back south. Baring in mind this isn't a siding, whereas trains can actually be stabled in sidings (rail grinding trains in Victoria & Liverpool St sidings come to mind), however if you're desperate anything is possible...

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

If I remember correctly the Jubilee line Charing Cross branch had some fairly long overrun tunnels, and probably don't need both platforms retained available, so probably park couple of trains there too.

Yes, this is correct however I should point out that the 24 stock doesn't have compatibility with the Jubilee line signalling, you could do a move under ITMP however...

 

[bluegoblin7]

Yes, this is correct however I should point out that the 24 stock doesn't have compatibility with the Jubilee line signalling, you could do a move under ITMP however...

Although before you even start to consider an ITMP you need to know if the trains will actually fit! Given the unique characteristics of the 24TS that's a big question in and of itself (ditto Aldwych branch), and if remedial works are required are they worthwhile for storage?

 

[Thirteen]

In regards to closing the T4 loop, would it mean less trains per hour going to Heathrow but also how does the T4 trains turn back?

 

[Peter Mugridge]

In regards to closing the T4 loop, would it mean less trains per hour going to Heathrow but also how does the T4 trains turn back?

I took it to mean a complete closure of the loop with passengers for T4 having to transfer to the Heathrow Express / Elizabeth Line for the free inter-terminal transfer?

 

[Crithylum]

In regards to closing the T4 loop, would it mean less trains per hour going to Heathrow but also how does the T4 trains turn back?

I think they would send all of the T4 trains to T5 instead

 

[Snow1964]

Although before you even start to consider an ITMP you need to know if the trains will actually fit! Given the unique characteristics of the 24TS that's a big question in and of itself (ditto Aldwych branch), and if remedial works are required are they worthwhile for storage?

The 1938 tunnels from Finchley Road to Baker Street, and the late 1970s Jubilee line tunnels were built to slightly larger diameter than the old Piccadilly line tunnels (and they don't have sharp curves following street layout).

If a similar batch is ever built for Bakerloo, then they might use this route to transfer to/from the line, so might be long term plan to check they fit anyway.

 

[bluegoblin7]

Just because the tunnels are physically bigger it doesn’t necessarily mean the train will fit - the suspended cars have very different characteristics to traditional stock, and things like cable runs added over the years may well impede in unusual places.

 

[Central]

Long Marston costs money and isn't exactly flush with space at the moment.
Heritage Railways would need to be sufficiently secured, which there just isn't much space for, especially such a long set that you can't realistically deliver by road, so can't really serve this purpose.

There is of course the "Global Centre of Rail Excellence" which was supposed to be built out with warm secure storage by now. How's that going?

The thing is, closing the T4 loop and using it to store units isn't actually the worst idea I've heard on this.

Also, good on Siemens for actually holding TfL to account on what appears to be their contract terms. Feels like TfL may be getting a taste of their own medicine here.

EDIT:
One also needs to consider powering the units while stabled to prevent there being issues when coming out of store. 630V / 750V double pole shore supplies aren't the easiest thing in the world to find.

Double Edit:

Wonder if there's any regret of not taking forwards the plans for a secondary depot at Ruislip for commissioning these new fleets. I would doubt it since most of the team that envisaged this approach have left, been pushed out or retired.

From the late 50s till the 80s all new rolling stock was delivered and commissioned at Ruislip Depot,there was a New Stock Engineer in charge.

 

[NoddyMaccy]

The cab is rather small and cramped, but they look smart.