However articulated trains need shorter carriages, because the distance between bogie centres is constrained. Therefore an articulated train of the same total length would have more carriages, and only a small saving in bogies. For example, on the Piccadilly a 73TS has six cars with a total of twelve bogies, while the articulated 24TS has nine cars with ten bogies. An articulated DLR train equivalent to the B23 would need at least six cars/seven bogies, but looking at the bogie centres on the existing units I think eight cars / nine bogies is more likely.
The new trains probably had to have more bogies to share the extra weight of air-con kit without increasing axle weight on some of the historic structures.
Lets be honest, we all sit at the front of the DLR so we can pretend to be driving. Copenhagen metro has had pseudo control panels under the front windows for a while now:
"Inflexible, fixed rakes" is regarded as an advantage in this case. The inter-unit gaps waste space that could be used for passengers and the couplers are wearing out from coupling and uncoupling. The DLR needs more capacity, the only reason they don't run all the current services as three-car trains is they haven't got enough rolling stock to do so at the desired frequency. Previously passenger circulating capacity at Bank was a limiting factor on running more trains there, but this has now been resolved.
Regarding non-articulated stock. Remember that the DLR has some very tight curves and steep gradients. Articulation points are inherently less flexible than couplers between cars, so this may have been a factor.
The essential things in life are seen not with the eyes, but with the heart. --Antoine de St. Exupery
90% of modern trains are 'inflexible fixed rakes' whether it be the S-Stock, the NTFL, the B23s, and the Aventras/Desiros/FLIRTS on the main line or whatever.
I think the horse has well and truly bolted on that front.
Cabs are also a major use of space, with (per cab) 0-2 staff members and equipment taking the same area as circa 4 seated passengers. Coupling and uncoupling units is costly in terms of time, capacity and money so, especially on metro services it is cheaper to run a train at a fixed length all day than to add or remove cars to account for expected capacity, so the cost-benefit calculation for cabs is usually negative. I suspect this is even more so post-pandemic given the relative flattening of peaks. In the days of steam locos, labour was cheaper, you had to shunt locos anyway and there was a much greater difference between the type of maintenance required by locos and carriages, so the equation was very different.
The essential things in life are seen not with the eyes, but with the heart. --Antoine de St. Exupery
90% of modern trains are 'inflexible fixed rakes' whether it be the S-Stock, the NTFL, the B23s, and the Aventras/Desiros/FLIRTS on the main line or whatever.
I think the horse has well and truly bolted on that front.
I think either your choice of 90% is low or your definition of "modern" very loose. The TransPennine Express Mk5 stock worked in fixed rakes, though I'm not sure about the Caledonian Sleeper carriages. Prior to that it's the 1990s Mk4 stock, which operate in fixed rakes. Bringing it back on topic for this forum, everything currently operates as fixed rakes, indeed on the Central Line cabs have been harvested for parts and are now condemned to being within a train.
90% of modern trains are 'inflexible fixed rakes' whether it be the S-Stock, the NTFL, the B23s, and the Aventras/Desiros/FLIRTS on the main line or whatever.
I think the horse has well and truly bolted on that front.
I think either your choice of 90% is low or your definition of "modern" very loose.
Yeah lack of knowledge on my part, I wasn't sure about the 2009TS or the Nova3's for example. Ta for the extra info.
The Greater Anglia Aventras are in 5 car sets that couple to form 10 cars for busier services so there's still a bit of coupling/uncoupling in service. Liverpool St mid to late afternoon if you are interested. Replaced trains with shorter cars in 4 car units that could make 8's or 12's.
Tube train cabs of the 1938 era were only a couple of feet deep, so narrow that I had to ride side-saddle to get my knees within the control desk. They only really featured a brake handle and a power controller. Modern trains provide a comfortable workstation, with controls for radio communications, passenger address, signaling interface, platform interface, safe door operation, etc etc. So they take up more space, and require a lot more investment in equipment which then requires maintenance. The fewer the better in a train. It's hard to imagine a time when shorter trains could operate as demand has increased throughout the day, and off-peak service intervals still allow travelers to turn-up and go. In the past a 30-minute service off-peak might have met demand on a branch, but was operated as a 15-minute service of half-length trains.
Steering back to DLR topics, shorter trains more often was the big change in the May 2023 timetable wasn't it. I assume that once the B23s arrive in force, more or less every service will be running full length, since the B23s can't be split and they should have enough trains to always run 3x of the older stock.
Almost but not quite. Even after the full deployment of the B23’s, including the extra Housing Infra Fund funded trains, the Stratford Int - Beckton service is planned to continue to be operated by short formed B07’s all day.
Child of Middlesex, student of the City, resident of the Metropolitan
Any idea how many units that service needs? Interested to know how many B07s that leaves.
Will the remaining B07s just run in threes everywhere and get mixed in with the B23s or is there another specific route we'll see the rest allocated to eventually?
Last Edit: Jan 17, 2024 17:37:10 GMT by goldenarrow: Quote removed
At the moment, I believe B23s will only operate from Beckton depot, so all "runs" that operate from Poplar will be B2007s. On the current schedule, the only route where all the trains operate out of Poplar depot is the Stratford (High Level) route. On all other routes, trains operate from both Poplar and Beckton depots.
This is, of course, subject to change
Last Edit: Jan 17, 2024 17:37:39 GMT by goldenarrow: Quote removed
Any idea how many units that service needs? Interested to know how many B07s that leaves.
Will the remaining B07s just run in threes everywhere and get mixed in with the B23s or is there another specific route we'll see the rest allocated to eventually?
I’ve only got partial notes to hand, but I *think* that Stratford Int - Beckton requires 6/8 trains off-peak/peak. In addition, the end-state plan puts the remaining B07s all as 3-car sets working Tower - Beckton (6/8 trains off-peak/peak) and Stratford Int - Woolwich (5/7 trains off-peak/peak), the latter being a mixed service with B23s. There are at least three stock/formation rotations before we get to that point though, so plenty of changes between now and 2026.
Child of Middlesex, student of the City, resident of the Metropolitan
Anyone heard the latest? The B23s seemed to be out and about during this weekend's closure, wondered if anyone knew whether we might see them in service next month as was hinted.
"The DLR rolling stock replacement programme carried out testing of a new train during a track possession. As part of the testing process the train slid and overshot its designated stopping point. Although this happened during a testing activity with no safety risk to others, the reasons need to be fully understood and an investigation is in progress to identify root causes."
"Manufacturing of the new rolling stock in Spain is continuing, with 22 trains completed. Main line testing is also progressing and signalling integration testing of the onboard vehicle signalling control system is underway."
"We encountered some challenges during integration testing works towards the end of 2023 which we are currently investigating. This has had an impact on delivery dates. We now expect the new trains to begin entering passenger service in Quarter 1 2024/25. Importantly, the end date for the renewal of the full fleet remains Quarter 2 2026/27."
[TfL Investment programme report Quarter 3 2023/24 (17 September to 9 December 2023)]
I wonder why it was decided to continue DLR train production whilst the original trains are under test. Problems discovered may require the modification of all 22 trains completed so far! Meanwhile only two Piccadilly Line trains are completed and under test. Lessons leant can be incorporated into the main production run. Both fleets are ordered by TfL!
Last Edit: Feb 21, 2024 2:54:05 GMT by jimbo: Final line afterthought!
The two parties (customer and manufacturer) will have agreed a delivery schedule for test train(s) and production trains, but I expect that the choice of when to manufacture them is entirely the manufacturer's. The customer will only make the final payments for the train once the agreed acceptance criteria are met, and so it's not generally going to be financially relevant to them whether the trains are modified post-production line or not (unless there are significant differences in life expectancy and/or maintenance requirements).
Whoever makes the decision, it will include consideration of the likelihood and likely significance of required hardware modifications. My guess is that the DLR's much more modern, relatively compact, relatively homogenous network was seen as having a lower risk of this than the Piccadilly line. The differences from the manufacturer's platform (and how established that platform is) will also make a difference.
The essential things in life are seen not with the eyes, but with the heart. --Antoine de St. Exupery
At the end of May there were 12 trains completed (see above), and 25 now, so 13 built in 5 months. By the time the first train enters service in March 2024 they will have completed about 38 of the 54, with the total build finished around the end of the calendar year. I can't recall a previous build that got so far ahead of entry to service. That requires a lot of costly storage space. And hopefully the current testing doesn't reveal fixes required for the whole fleet! The 2009TS pre-production pair of trains were scrapped after testing since so many modifications were required for the fleet build that it was cheaper to start again! .....
Some doubt on build rate as latest report is 22 trains now built, but taking 13 built in 5 months, will be introduced to service at 10 in 5 months, or two trains per month, so no faster than build rate. Won't catch up the backlog, and 54 trains will take 27 months to enter service until mid-2026.
"Manufacturing of the new rolling stock in Spain is continuing, with 22 trains completed." [TfL Finance Report, Period 11, 2023/24, Management results from 1 April 2023 – 3 February 2024] So it looks like manufacturing of the new rolling stock in Spain is not actually continuing, with no change in the number built since my 30 November post, over three months back! Well at least two months before period end 3 February 2024.