DLR B23 Stock (CAF Inneo)

Taunton said:

That doesn't square with things on a few counts

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I think it squares pretty well with the delays we're seeing. Projects like this don't usually have technical details widely discussed in public. Crossrail only did at the point it became a national scandal, and even then things were often left fairly vague.

On the national network we've seen more than a few examples of newer signalling installations retired before older ones - usually due to hardware obsolescence rather than software, but then the DLR must use the oldest ATO software still in use in the country, so software difficulties shouldn't be surprising.

At this point, would it not be easier to write new software from scratch fit for 2025 rather than trying to adapt 90s software?

OneTrackMinded said:

Looks like another unit is finally being delivered.

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Unit number 238

Taunton said:

- Signalling from the 1990s is not "antiquated"; probably more than half the national system uses what is older. The current system does seem to run pretty faultlessly.

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The version of Seltrac used on the DLR is antiquated in so far as it is no longer offered for sale. Hitachi recently (2024) purchased the product from Thales, and I strongly suspect that there are no longer any members of staff on the team familiar with the legacy version.

So.... it seems that no-one realised that the signalling system had been tweaked for the trains - maybe this was not so much an oversight on behalf the people who wrote the specification for the new trains as something never encountered before and therefore totally outside of a reasonable expectation.

The real issue here is that this is one of the first times* that a new fleet of trains has been introduced on an automated railway (in London) with the expectation that they will use an existing automated train control system and we are realising that nothing is always as easy or as simple as expected. The phrase 'steep learning curve' comes to mind.

As an aside, the Victoria line was different because its new trains were only intended to use the existing signalling as a short-term fix prior to the enablement of a brand new and more advanced ATC system, and therefore this issue was planned as part of the fleet replacement programme.

I wonder how the Parisians coped with the introduction of new trains and subsequent conversion of metro lines 1 and 4 to fully unstaffed automated trains? Perhaps they adopted the Victoria line solution? If not, is there a lesson here that also needs to be learnt to prevent future issues / problems?

*(I have Singapore, Hong Kong and several French VAL rubber-tyred systems in mind as also having done this, but am unsure if they used the same or upgraded ATC systems)

simple simon said:

I wonder how the Parisians coped with the introduction of new trains and subsequent conversion of metro lines 1 and 4 to fully unstaffed automated trains? Perhaps they adopted the Victoria line solution? If not, is there a lesson here that also needs to be learnt to prevent future issues / problems?

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Lines 1 and 4 switched to driverless operation without any service interruptions. Driver-operated and automatic trains were in service at the same time during the transition period, with the new trains progressively replacing the older ones over the course of a few years.

Roast Veg said:

The version of Seltrac used on the DLR is antiquated in so far as it is no longer offered for sale. Hitachi recently (2024) purchased the product from Thales, and I strongly suspect that there are no longer any members of staff on the team familiar with the legacy version.

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Which then brings me on to my next question would it make sense for when the trains eventually all get into service to thrn possibly resignal the whole network to an updated version to ensure a situation like this doesn't occur in the future. As the famous saying goes. Buy cheap pay twice.

The other rolling stock almost certainly precludes that.

Kay_M said:

Which then brings me on to my next question would it make sense for when the trains eventually all get into service to thrn possibly resignal the whole network to an updated version to ensure a situation like this doesn't occur in the future. As the famous saying goes. Buy cheap pay twice.

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Until the next major change, of fleet or of signalling

35B said:

Until the next major change, of fleet or of signalling

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Ah touchè

Spotted unit 203 on test back on Saturday 17th May at West Silvertown, heading towards Stratford. Photos by me.

Sunil_P said:

Spotted unit 203 on test back on Saturday 17th May at West Silvertown, heading towards Stratford. Photos by me.

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Looks good.

Mention of the DLR new fleet in latest Commissioner's Report:

Work continues to prepare for the introduction of the new trains, alongside rectifying the signalling issues we found last year. Since restarting train testing, we have made good progress and completed testing of the line-side signalling system. While significant assurance activities still need to be completed, we remain on track to introduce the first new train later this year and replace the B92 fleet by the end of 2026 as originally planned.

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The Beckton Depot expansion also continues at pace alongside wider works across the DLR network, including the recent opening of the second entrance at Blackwall station to customers. To further support the introduction, and to extend the working life of the fleet that the new trains will replace, we amended the DLR timetable between 7 April and 25 April. Further service changes will be required from this summer as we continue to manage the current fleet ahead of the introduction of new trains, due to start later this year. We will provide further details of these once they have been confirmed.

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