SSR resignalling

[GFE]

SMA10/12 seems rather ill fated - There was an issue found shortly before the testing closure in Oct 25- This meant a further iteration of fixes/development and the postponement of the commissioning penciled in for Jan 26. So presumably there will be another cycle of circa 4 months for arranging another closure & time for fixing/retesting things.
Noting that the remaining SMA's on the Met have a number of innovations (because of the non- CBTC equipment trains), lets hope they are progressing better and there is enough confidence/assurance that the booked Aug 26 closure can be the commissioning.

 

[zwk500]

SMA10/12 seems rather ill fated - There was an issue found shortly before the testing closure in Oct 25- This meant a further iteration of fixes/development and the postponement of the commissioning penciled in for Jan 26. So presumably there will be another cycle of circa 4 months for arranging another closure & time for fixing/retesting things.
Noting that the remaining SMA's on the Met have a number of innovations (because of the non- CBTC equipment trains), lets hope they are progressing better and there is enough confidence/assurance that the booked Aug 26 closure can be the commissioning.

The reports for the July 1 meeting of TfL's Programmes and Investments board have been released and include a 4LM update: https://board.tfl.gov.uk/documents/...ground Four Lines Modernisation Programme.pdf

The critical bits:

4.7 It is planned to commission the new signalling system on the District line between Barons Court to Stamford Brook (SMA10) and Fulham Broadway to East Putney (SMA12) in summer 2026. This will complete the planned roll out of the new signalling on the District line (noting that as reported to the Committee in July 2021 the sections of the District line south of East Putney and west of Stamford Brook will remain under the existing signalling).

4.8 Software development and site system testing has been completed for SMA9 (the Harrow area). SMA9 is another complex area as it involves integration of the new automatic signalling system with manually driven Chiltern trains, requiring novel system functionality and significant operational readiness training. The Programme is now focusing on the final preparations for the commissioning of SMA9 with go live planned for later this year.

4.9 Beyond SMA9, further progress was made in February 2026 when we completed our first system test for SMA13 (Moor Park to Watford, Chesham and Amersham). Software development and system testing will continue for this area over the next year ahead of a planned go live in the second half of 2027. We expect to start the software development for the final SMA (SMA14 Rayners Lane to Uxbridge) in 2027.

5.4 Considering the above, our forecast completion date for the final SMA (SMA14 Rayners Lane to Uxbridge) going live is now expected to take place in 2028

It's not clear if the report was updated to reflect SMA 10/12 being called of, which impacts if the 'summer' means still trying to get it in before the end of August or if it was intended to be the june dates.

So we have the following go-live dates:
SMA9 - 'later this year'
SMA10/12 - Unknown (postponed from June 2026)
SMA13 - 'second half of 2027'
SMA14 - 2028

 

[A60stock]

I see that since I last mentioned it, no efforts have been made to rectify the sluggish speed on the Southbound between Neasden and just north of Kilburn. This section was previously very quick when CBTC first came in.

I really hope the speed on that section will be improved soon.

 

[Dstock7080]

SMA10/12 commissioning now rescheduled for 22-23 August, (the previously announced SMA9 Go-live date).

 

[zwk500]

SMA10/12 commissioning now rescheduled for 22-23 August, (the previously announced SMA9 Go-live date).

Does this mean SMA9 is pushed back or will all 3 go live on the same weekend?

 

[Edvid]

Does this mean SMA9 is pushed back or will all 3 go live on the same weekend?

The Investment Programme milestone for SMA9 commissioning is 30 November 2026.

The SMA10/12 equivalent is 30 September 2026 though as noted by Dstock7080 TfL are making a second attempt to do it 'early'.

 

[eastrail]

Looks like SMA 10/12 is being reattempted later this month. I don’t think it was explained in detail before, so I would like to ask a few questions regarding the closure.

• Is the majority of SSR being closed before 10:30 on Saturday to do with a SelTrac-wide upgrade?
• During the migration weekend, why are trains running across the new CBTC boundary at Stamford Brook but not at East Putney?
• Am I correct in thinking in previous migrations, that the trains were not in service for the entire line/section in question?
• Will line speeds or acceleration rate anywhere on the SSR be increased?
  • Does anyone know what the max speed between Paddington Praed Street and Victoria is?
  • What determines whether a section of track gets to have faster acceleration? For example, Euston Square WB has very fast acceleration but EB is much slower and both had CBTC for a while.

And on a side note, I would also like to ask a few things about SelTrac on the Jubilee line.

• I noticed a 3-aspect signal at Baker Street SB. I assume Blue means ‘communicating with TBTC (and with movement authority)’ and will route the train to Bond Street. What would be the aspect shown for any train heading to Regent’s Park?
• What is a EP sign? I would assume RM hold boards act similarly to the Northern and SSR counterpart, albeit with a different design.
  • I also saw a cab view video showing that the connecting tunnel from the Bakerloo to Jubilee northbound at Baker Street shows an EP sign as well. How does the changeover from manual to TBTC work here?
• On entry and exit at Neasden depot, is it the Jubilee line TBTC or SSR CBTC controlling all of the trains? Or does only one system work at a time?

I admit that these are indeed a lot of questions, but any insight would be much appreciated!

 

[Kay_M]

Looks like SMA 10/12 is being reattempted later this month. I don’t think it was explained in detail before, so I would like to ask a few questions regarding the closure.

• Is the majority of SSR being closed before 10:30 on Saturday to do with a SelTrac-wide upgrade?
• During the migration weekend, why are trains running across the new CBTC boundary at Stamford Brook but not at East Putney?
• Am I correct in thinking in previous migrations, that the trains were not in service for the entire line/section in question?
• Will line speeds or acceleration rate anywhere on the SSR be increased?
  • Does anyone know what the max speed between Paddington Praed Street and Victoria is?
  • What determines whether a section of track gets to have faster acceleration? For example, Euston Square WB has very fast acceleration but EB is much slower and both had CBTC for a while.

And on a side note, I would also like to ask a few things about SelTrac on the Jubilee line.

• I noticed a 3-aspect signal at Baker Street SB. I assume Blue means ‘communicating with TBTC (and with movement authority)’ and will route the train to Bond Street. What would be the aspect shown for any train heading to Regent’s Park?
• What is a EP sign? I would assume RM hold boards act similarly to the Northern and SSR counterpart, albeit with a different design.
  • I also saw a cab view video showing that the connecting tunnel from the Bakerloo to Jubilee northbound at Baker Street shows an EP sign as well. How does the changeover from manual to TBTC work here?
• On entry and exit at Neasden depot, is it the Jubilee line TBTC or SSR CBTC controlling all of the trains? Or does only one system work at a time?

I admit that these are indeed a lot of questions, but any insight would be much appreciated!

So EP stands for Entry Point. It's used when there's a signal failure and a procedure would need to be carried out. An EP board with an X on it would be the clearance point. (Limit of the move). I'm sure someone else on here can go into more detail but I'm explaining the simplest version

 

[Dstock7080]

• whole CBTC system closes for software updates
• it is true about East Putney, no explanation except possibly NR interaction. Operational proving trains will be operating across the boundary on Sunday 23.
• line speeds for this new section are not available yet. The maximum speed between Paddington and Victoria is 62mph Bayswater-High Street.
• entering Neasden depot the reception roads are specially dual-fitted with both systems. A train approaches in PM Protected Manual and stops at the CBTC TBTC sign and switches to Restricted Manual to enter the depot under Depot Rules Apply.

 

[A60stock]

I have read that the reason the District to Ealing hasn't been done is because they don't see the point in resignalling until more is known about what system the Piccadilly will use.

Makes sense to me but then doesn't the same logic apply for the Uxbridge branch, shared with the Met, yet that clearly has had all the necessarily equipment installed?

 

[Dstock7080]

The West Harrow-Uxbridge section is a Metropolitan asset.
Turnham Green-Hanger Lane junction is a Piccadilly asset.

 

[starlight73]

I have read that the reason the District to Ealing hasn't been done is because they don't see the point in resignalling until more is known about what system the Piccadilly will use.

Makes sense to me but then doesn't the same logic apply for the Uxbridge branch, shared with the Met, yet that clearly has had all the necessarily equipment installed?

It was mentioned a (long) way up thread that the Metropolitan signalling is older so it requires replacement sooner.

[...] Metropolitan will be completed as its signalling equipment is older, and patching it up for years is likely to cost more than finishing the replacement.

Eventually the descoped sections will end up with equipment which has become non standard (as it will be relatively small part of network), and probably be harder to get spares and maintain. But for time being seems to be in the defer for next 5, 10, 15, 20 years (or whenever) category.

SSR resignalling

If the train has to stop, how can the statement ”will not impact on journey times” be true?

www.railforums.co.uk

== Doublepost prevention - post automatically merged: 2 Aug 2026 ==

And also in post #452 which explains that one of the difficulties was that the Wimbledon/Richmond branches are signalled by Network Rail and their systems cannot be completly replaced with CBTC. And that Acton Town is very complex to resignal.

The key difference between SMA9/13 and SMA10/12 is that the Met is wholly owned and operated by LUL, and Chiltern trains run over LUL infrastructure. Therefore, CBTC can provide the primary interlocking (‘underlay’) which drives the lineside signals. Technically, this is relatively simple to achieve and something LUL have total control over.

For the Wimbledon and Richmond branches this obviously isn’t the case: signalling is provided by Network Rail, and so a CBTC ‘overlay’ is (was) required that is derived from the existing signalling. Given the nature of these assets - and the more limited abilities to access them - this is a much more drawn out process, and there were also some contractual issues between LUL, NR and Hitachi/Thales, all of which was for relatively little overall gain.

The complexity of the Acton Town area was the main reason for descoping SMA11 - whilst technically the same as SMAs 9, 13 and 14 (CBTC underlay) it becomes of limited additional value given the restrictions imposed by ‘legacy’ (Piccadilly) rolling stock, and the fact that the S7 fleet will still require tripcocks to be fitted and maintained given the descoping of Wimbledon and Richmond. It is, however, simply pushing the problem down the line - unless the Picc receives the same flavour of CBTC (unlikely) there will almost certainly be further issues on the same scale as seen by the Wembley Park/Neasden mixed mode area where two/three different signalling systems all have to interface. What has been implemented can best be described as a bodge.

Finally, as already mentioned, the legacy kit in these areas isn’t as life expired as that on the Met. The main pusher is to allow Earl’s Court control room to completely close, removing some significant unreliability there. As mentioned, Wimbledon and Richmond would have retained the existing interlocking anyway, and most of the unreliability of the Acton Town area was resolved by the Piccadilly Interim Control Upgrade (PICU) project a few years ago, which introduced a new control room and signalling interface to the Piccadilly and west end of the District.

 

[GFE]

I believe the Uxbridge branch signalling not as old as the rest of the met, but as the met is the predominant service over it I agree there i a benefit to upgrading it.

 

[A60stock]

Had a feeling it was in part due to the fact that the Met "owns" the Uxbridge branch with the Piccadilly as a supporting service, whereas on the shared sections with the District (in particular the Acton town area), the Piccadilly "owns" that side.

Regardless, I would have thought tfl would want to minimise the amount of non CBTC sections but I guess as the Richmond and Wimbledon sections are not being done, it does not make the Ealing branch as crucial to do.

One thing which will be interesting is the fact that every single s7 stock will need to keep the tripcock equipment, which is surely going to add on a significant amount of cost to maintain just for a small sections of the West end District. Have tfl considered removing tripcock equipment on some s7s? So these would be confined to the Circle, H&C services?

 

[Kay_M]

Had a feeling it was in part due to the fact that the Met "owns" the Uxbridge branch with the Piccadilly as a supporting service, whereas on the shared sections with the District (in particular the Acton town area), the Piccadilly "owns" that side.

Regardless, I would have thought tfl would want to minimise the amount of non CBTC sections but I guess as the Richmond and Wimbledon sections are not being done, it does not make the Ealing branch as crucial to do.

One thing which will be interesting is the fact that every single s7 stock will need to keep the tripcock equipment, which is surely going to add on a significant amount of cost to maintain just for a small sections of the West end District. Have tfl considered removing tripcock equipment on some s7s? So these would be confined to the Circle, H&C services?

In theory that would work but then let's say one of those trains assigned to the H&C/Circle is defective they would need to borrow one from the district which could then leave the allocation a bit lop sided and vice versa so to save time it's better to keep it intact so they can mix around as and when.

 

[plunet]

And of course the Met permanently has a least one S7+1 in service, although I doubt that would be first in the queue for a swap to another line.

 

[Dstock7080]

SMA10 Barons Court-Stamford Brook went live for passenger use from 16.10 yesterday, 22 August 2026

 

[zwk500]

SMA10 Barons Court-Stamford Brook went live for passenger use from 16.10 yesterday, 21 August 2026

Is that the completion of the (amended) planned work on the District Line, or is there a small amount of SMA12 left?

 

[Dstock7080]

Is that the completion of the (amended) planned work on the District Line, or is there a small amount of SMA12 left?

SMA12 awaiting commissioning later today or for tomorrow start of service.

 

[bluegoblin7]

Once SMA12 is in today or tomorrow morning that is the end of current resignalling plans on the District line, yes. SMAs 9, 13 and 14 remain at the top end of the Met, with the remainder of 10, 12 and the entirety of 11 descoped.

 

[zwk500]

SMA12 awaiting commissioning later today or for tomorrow start of service.

Once SMA12 is in today or tomorrow morning that is the end of current resignalling plans on the District line, yes. SMAs 9, 13 and 14 remain at the top end of the Met, with the remainder of 10, 12 and the entirety of 11 descoped.

Thanks both for confirming. Is there a public date for SMA 9 yet?

 

[djw1]

Is the “operational incident” that’s got the lines suspended at the minute related to this?

 

[GFE]

SMA9 was scheduled for this weekend, but then postponed to do the aborted SMA12. So strong indications that the design & installation and testing of SMA9 done/ready. The business target date was before end 2026 but difficult to get agreement for a weekend closure of Met that is required to do the commissioning & nothing on the published 6 month look ahead of planned closures.

 

[Harsig]

SMA10 Barons Court-Stamford Brook went live for passenger use from 16.10 yesterday, 21 August 2026

Nice to see Automatic Train Operation reinstated between Stamford Brook and Ravenscourt Park a mere 63 years after it was first introduced.

For those that don't know a trial installation of the ATO system that would eventually be installed on the Victoria Line, was brought into use between Stamford Brook and Ravenscourt Park eastbound only in April 1963. Previous trials had been held on the test track at South Ealing, but I believe the Stamford Brook to Ravenscourt Park installation was the first to convey passengers. Only one east facing R stock Driving Motor was equipped with ATO equipment so the trial was limited to that single train. A year later a much bigger trial installation was brought into use on the Central Line between Woodford and Hainault.
I'm sure I've seen film of the District trial, but cannot remember where. In the meantime here are a couple of links to pages which give more information.

https://londonist.com/london/transport/first-automatic-london-underground-tube-train-1963

http://news.bbc.co.uk/onthisday/hi/dates/stories/march/21/newsid_2546000/2546071.stm

 

[Kay_M]

SMA10 Barons Court-Stamford Brook went live for passenger use from 16.10 yesterday, 21 August 2026

Splendid news and you mean 22nd August right?

 

[OneTrackMinded]

Just had a ride on the section and it’s really good, full power acceleration out of stations and full power deceleration into stations.

 

[Dstock7080]

SMA12 Fulham Broadway-East Putney went live for passenger use from first trains this morning, 24 August.

 

[Belperpete]

SMA12 Fulham Broadway-East Putney went live for passenger use from first trains this morning, 24 August.

Does that mean the Passenger Information Systems at Earls Court, West Brompton, etc are now showing useful information?

 

[ijmad]

Does that mean the Passenger Information Systems at Earls Court, West Brompton, etc are now showing useful information?

The web feeds (which come from the signalling system) are still showing a lot of 'Check Front of Train' destinations which doesn't fill me with a lot of hope.

 

[bluegoblin7]

It usually takes a few days for the feeds to catch up as it involves different teams and cannot be done in advance, especially in the event of last minute hiccups or postponement.

I am reliably informed that PIDs in the area are showing enhanced and correct information.

PID = Passenger Information Display, Train Describer in old money.