London Underground’s SMA3 goes live!

The third part of London Underground’s CBTC conversion has taken place. Like all other previous conversions, this was marked by the start of public services a day earlier than advertised. The lines in question were advertised as having no services until the Monday morning, but an unofficial service (as has been the case in every previous situation since SMA 0.5) was invariably provided on the Sunday afternoon. Its been said the latest change went without a hitch and for the first time it includes the District Line proper between Monument and Stepney Green. It also means the entire north side of the Circle Line and most of the Hammersmith & City is now CBTC, with the latter now having just eight non-CBTC stations out of 29 stops.

Service changes occurred on Saturday, March 6 and Sunday, March 7 2021 this being to facilitate the implementation of SMA3 like all the other previous occasions. Each has followed what is now a predictable pattern. Unlike the previous conversions however, the last of which occurred before the coronavirus pandemic, there’s been very little information on this latest, thus I have tried my best to fill in the gaps. Its been more than a year and a half since the last such instance of CBTC, which was the end of August 2019! (I wrote about that here.) The SMA3 to Stepney Green (and Monument) was originally envisaged to be active in 2019 and the Four Lines Modernisation is now almost two years behind schedule.

Barbican’s coffee pot signal seen just a few hours after services began.

The Four Lines Modernisation as it is called is clearly quite behind in terms of when each stage was supposed to be implemented and in part that is no doubt due to the pandemic. Its been said some parts of the conversion have been dropped (descoped is the word being used) such as on the branches to Ealing, Richmond and Wimbledon whilst other sections have been delayed considerably. However the next stage is due to be implemented quickly and that is SMA 4 on the 24 and 25 April 2021 from Monument to Sloane Square. The next, SMA5, is provisionally pencilled in for September 2021. As a matter of fact, TfL had previously asserted the entire Circle Line would be CBTC controlled by the end of 2019 in readiness for a major timetable recast from 2020. No doubt that confirms that the scheme is two years behind, and by the time SMA5 comes in at the end of this summer (if it indeed does) TfL will be pushing it in order to prevent further slippage in the timetable. As a result some of the later iterations of the scheme (as mentioned earlier) have been dropped (at least for now) in order to focus efforts on the remaining aspects of the project which are more critical than say, Wimbledon or Richmond.

Euston Square, previously the extent of CBTC since August 2019. H&C train seen here on the first day of automated train working eastwards. The station’s last working coffee pot signal is seen just above the train wrapped up in black.

One interesting aspect of this latest stage will be to see whether the new sidings at Farringdon do in fact now get built and are used for train berthing. When the junctions were first laid at Farringdon about three years ago, there was little point in providing traditional signals onto a section of line that would in essence be CBTC anyway. Of course nothing could be done whilst the works to build Crossrail were underway. In the summer of 2020 it was said the works had been deferred for a year. Now that the running lines are CBTC there is no reason to delay any further that section of the overall upgrade work. It is an important upgrade of course because it would mean all the depots/berths for the Hammersmith/Circle/Edgware Road-Wimbledon services can essentially be concentrated entirely within CBTC enabled locations – thus no longer would there be any need to take trains trains to Ealing Common, Neasden or Upminster – except for heavy maintenance and repair. The sidings at Parsons Green are an exception but these wouldn’t be injurious to the scheme of things because the ‘Wimbledonware’ trains will use traditional driving methods between Fulham Broadway and Wimbledon for a considerable amount of time to come.

District Line for Ealing Broadway entering Stepney Green and the start of the new CBTC section on its first day of public operation.

In terms of London underground signalling history, the upgrade has seen another tranche of coffee pots signals taken out of use. These are those at Euston Square (eastbound), Barbican (both directions) and Liverpool Street (both directions.) It means there are no longer any operational coffee pot signals anywhere in the central zones of London Underground. There’s just one coffee pot signal still at work on the District Line outside of the central zones, although that I believe isn’t as old as the others were. In terms of signalling too it means other types including split four aspect signals and rail gap indicators have been made redundant. However that at Liverpool Street (adjacent to CBTC MRG 011) has been retained as has one or two others, they’re now tied into the CBTC system. All the other signals that have been taken out are various mixes of two, three and four aspect colour light signals.

Liverpool Street’s unusual mix of CBTC control and traditional rail gap indicator.

The only working signals to ‘guard’ the ends of the new sections are those at Stepney Green and Monument. Certainly those signals at Monument are very unusual because the westbound platform signal is I believe LUL’s one and only single lens example on the sub surface lines which shows two different aspects. Of course there are single aspect signals on parts of the deep level tube lines that have been introduced as a result of automated train operation – but these lines rely on different, in fact older ATO systems which require visual indicators to aid operations. Some of the signals on the section between King’s Cross and Liverpool Street are also quite unusual, there has been a considerable mix of different types of signals along this section from the very old to the more modern types, and all of these have had their day. The introduction of CBTC will ensure certain standards and software upgrades can be populated right across the system, making the entire system wholly consistent rather than constituting a total mish mash of colour light signal types.

Chesham train seen on the Metropolitan’s first day of CBTC through Liverpool Street. The station’s redundant westbound coffee pot signal is seen wrapped in black. And the pigeon? Looking for a ride no doubt!

In terms of train operation it seems the CBTC was a little touchy like on all its other previous iterations, more so on the very first day. That is, in terms of how the trains themselves had a slight sort of indecisiveness when trying to draw up correctly at the specified platform stops. Trains passing through Whitechapel non-stop however did that well, there was no discernible shift in motion rather it was the opposite. They maintained their pre-Whitechapel approach speeds through the station itself so I guess it was simply a case of ensuring the S Stock could maintain that former exact speed, and the trains didn’t flinch either side where there’s a quite steep gradient leading to the tunnels towards Aldgate East or Stepney Green.

The eastern end of the platforms at Stepney Green with traditional signals towards Upminster on the first day of full public operation.

For the District Line drivers there seemed to be some delay in switching the trains out of CBTC at both Stepney Green and Monument. The Hammersmith line’s drivers were no doubt more familiar with the CBTC. The one biggest change of all compared to the other SMA introductions was the fact no additional staff of any sort were to be seen at Euston Square, Monument or Stepney Green, waiting to assist if any problems arose with the CBTC at those transition points. I think it shows London Underground has far more confidence its CBTC will work practically straight off the bat – and there wont be any of the messiness such as that which prevailed on the Metropolitan for many weeks after CBTC had been introduced between Finchley Road and Euston Square.

The Metropolitan Line on its first day of full CBTC operation between Baker Street and Aldgate. How soon will the former railway alignment on the right be brought into use as S7 stock sidings?

On the Monday train operations seemed even better, there being none of that stickiness apparent the previous day, though some station starts seemed a bit slow still. One thing observed that hasn’t been seen on the previous occasions, was S Stock suddenly changing their headlights very briefly to the red tail lights and back almost immediately whilst in motion – I’m not sure what to make of that! Other things also included door lights and door not in use signs remaining on when the train was underway, as well as CBTC lights coming on after the train has actually got underway – the same sort of things that have been apparent in all of the CBTC iterations seen so far. As these don’t seem to impinge on the train’s overall performance or the integrity of the system itself, one must assume these things are just mere quirks.

CBTC sign by the new Farringdon junction.

The service alterations on the four lines affected over the weekend of 6/7 March was as follows:

Circle: The entire line was closed on Saturday to 10.30am. After 10.30am on Saturday a service was provided from Euston Square to Monument via High Street Kensington. On the Sunday there was no service at all, it is said due to a shortage of serviceable trains. As it turns out only the H&C ran on the north side from 14.00 on Sunday with a service every 15 minutes whilst the District ran on the southern side with a good service.

District: There was no service between Embankment and West Ham on Saturday before 10.30am. From 10.30am on Saturday and before 14.00 on Sunday there was no service between Monument and Stepney Green. After 14.00 hrs services were provided. Whitechapel Station was closed all weekend for Crossrail works.

Hammersmith & City: The entire line was closed on Saturday until 10.30am. Before 10.30am on Saturday and on Sunday until 14.00hrs no service was provided between Euston Square and Stepney Green. A barebones service every 15 minutes was provided after 14.00 hrs for the remainder of the Sunday. As has been mentioned, Whitechapel Station was closed all weekend for Crossrail works.

Rail gap indicator at Farringdon gets a wrapper!

The Metropolitan too was shut to facilitate SMA3. There was no service between Wembley Park/Baker Street and Aldgate. Monday 8th March would of course be the first day of CBTC operation between Euston Square and Aldgate. Although it can be said quite ironically Aldgate saw full CBTC operations on the first day in the form of both Hammersmith and District Line trains which passed the very ends of its platforms, the station would have to wait a full day before trains actually began using its four platforms.

From that day too, this being the Monday, the very first terminus platforms located within the City of London have now become CBTC operated, this being the platforms at both Moorgate and Aldgate. The Metropolitan and Hammersmith trains seemed to deal with the Liverpool Street to Aldgate section in a way the ‘driving’ seemed more certain. In other words instead of being slowed down or stopped by the signals en route the train seemed more certain of the route ahead and was adapting its speed to match and no doubt the computers were probably juggling the train’s speed as well as others in the vicinity. It would be interesting to see how this benefits the Circle, Hammersmith and Metropolitan lines as a whole – because in the past during rush hours the whole system back towards Kings Cross (or further) was compromised by having a queue of trains all the way to the Aldgate junctions because all these trains trying to get onto their respective routes there! Would CBTC reduce the instances in which those really appalling delays occurred?

‘Next CBTC train!’ Aldgate on its first day of automated train operation.

I couldn’t tell you how that would turn out – but nevertheless when passenger numbers do eventually get back up and there is great pressure on ensuring a smooth railway operation, that will be the real test for LUL in terms of its CBTC operations. Evidently one idea behind having CBTC is that the computers at the Hammersmith Control Centre would see what trains were operating in certain areas – for example in the Aldgate area a conflicting westbound Hammersmith or Metropolitan train coupled with several eastbound trains heading in three different directions, and whether the computers could jiggle the commands to the various trains as such to make sure they all came through the junctions and crossovers and along the various tracks seamlessly in a way that is far more efficient and prodigious than currently possible with manual driving.

The Metropolitan’s CBTC ends right here at the train stops in Aldgate station!

Of course one of the advantages is that CBTC is supposed to enable a smoother service, and in the long run the intent is to enable a far greater service frequency than was possible under the old system. Thus I think Kings’ Cross to Aldgate (and even Whitechapel westwards in both directions) will be very interesting to see – when it does come to the crunch – how the system in fact manages. It will show us the real capabilities of the CBTC system and whether it can manage such situations efficiently. So far that hasn’t actually happened because there’s been the pandemic and the rest of it, you know, few people using public transport and the rest of it. London’s underground has had a relatively easy going for almost a full year now. In fact such occurrences as those on the Widened lines and beyond to Aldgate will be LUL’s very own litmus test to show whether CBTC is really as adept as it is often made out to be

LU three aspect westbound signal at Moorgate on the first day of CBTC operation.

Aldgate is these days the furthest into the City one will find a terminus (or a dedicated turnback platform) so really its a quirk in terms of the London Underground. The former terminal platform at Tower Hill is now a through line thus it doesn’t count as such and the next, that at Mansion House, was removed a good number of years ago, thus there are no longer any dedicated turnback roads on the combined Circle/District route between Aldgate and Gloucester Road junctions. The next terminus (or turn back) arrangement of any sort on London’s underground to switch over to CBTC will be those at High Street Kensington and Olympia, possibly sometime in 2022 and that in a nutshell will be the last of the terminal platforms to be signalled as such until automated train conversion reaches the outer terminals on the sub surface lines system such as Ealing Broadway, Upminster, Amersham and so on.

The westbound starter signal on the eastbound Moorgate platform, with its equivalent CBTC sign on the left.

Moorgate station will be the underground’s first real test with an offset double tracked terminus served by a single lead junction. So far all the terminal platforms have all been derived from traditional rail layouts (Baker Street, Edgware Road, Hammersmith, and now Aldgate) with twin crossovers and double, triple or quadruple track. However that at Moorgate poses a problem because of its 1960s rebuild when the layout was switched from a traditional two and four tracked approach to become what now is two through tracks with a single lead onto a pair of terminus platforms. Its not even like that other offset terminus at High Street Kensington where a double tracked and double crossovers approach is retained. Thus the means of getting a train into the terminal platforms at Moorgate is even more critical than anywhere else especially during rush hours.

Much older LU split four aspect signal at Vine Street now under wraps.

Westbound District train at Monument, the current end of the line’s CBTC on its first operational day.

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