TBTC Testing

Ah; so an engineer is only defined by the parameters of the test case, these days?

I thought that 'engineers' tended to look beyond the data - you know empirical data and all that jazz - within reason the requirement can be defined on the basis of the data gained. I don't believe for one moment that there was no test case - if there were not then there would not have been so much 'test running'



Either that, or those that remain choose not to be proactive.

Is the route in ATO yet? Ive been told its driven manually but how come it does the keeping to target speed power on/off thing then?

The speed into West Ham eastbound wasn't glacial yesterday (the train was already in the platform at Canning Town when I arrived), but was slightly slower than I remember at Stratford.
The problem was, despite there being a "good service" on the entire line, we sat in West Ham platforms for nearer 5 minutes than 1. The reason given by the t/op was "Congestion between here and Stratford due to significant delays elsewhere on the line."

I can't really say I've noticed a noticeable increase in speed now trains south of Dollis Hill are in ATO. I know trains on the Jubilee always used to approach platforms really slow (especially on the platforms with Peds) but there doesn't seem to be much of a change recently; I don't seem to feel trains approach the platforms at fast speeds like on the Central or Victoria.

Am I imagining things, or will they speed it up soon?

Which is wholly understandable at this stage in the game. The emphasis must be on integrity and reliability, rather than speed, until the system is proven.

Monitoring the departure boards at various times today – if the TfL website is to be believed, regularity appears to have improved somewhat, with pretty constant 4 minute intervals at most stations, suggesting not only that the system is bedding in, but also that the service is being effectively regulated.

Where's that then? Is it in one place or distributed?

Something tells me it's at the main signalling centre; Neasden or Baker Street, can't remember which is such. It's to do with running trains to the timetable; perhaps someone a little more knowledgeable on the matter could give a little more detail.

Well you need to leave something in the bag otherwise you'll never be able to make up for any late running; and the current theory of LU and NR timetabling is to leave lots of recovery time to ensure trains run on time (it matters much more that a train arrives within X minutes of when it was scheduled than it does that journey times are as quick as possible^[1]), which will have an effect.
Probably the main reason though is that the current timetable is written around the capabilities of tripcock running, not ATO, while allowing for the inevitable hiccups and teething troubles that introducing TBTC and ATO brings. When the reliability of all aspects of the system has increased and the technology has bedded in^[2] then I would be very surprised if we don't see a new timetable that takes advantage of it. The Central and Victoria lines are not presently introducing a new system, and are long past this testing phase.

[1]Several threads in the District Line and SSR boards that discuss this, one of the threadfinders will give a link to one or more if they think it necessary.
[2]This could be done in two stages, i.e. take advantage of the technology south/east of West Hampstead before the northern/western end of the line is complete, then upgrade the timetable for that section when it's ready; or wait until the entire line is ready and do it all in one big bang (hopefully not literally!). I do not know which is planned.

The Central/Victoria lines have antiquated signalling systems and hence do not have anything of sorts. The idea is to keep trains to a timetable, rather than just gunning it.

I wouldn't call 1991-2001 vintage antiquated (or else I'm way over the hill, despite being quite young by LU standards)!

In terms of ATO systems, it is rather antiquated! Bear in mind that it is fixed block.

Isn't distance to go signalling near enough moving block?

(Sorry for going a bit off topic from the thread, mods/gods...) Unfortunately, I think we all know the Tube is operating to what essentially is maximum capacity. When Woolwich Arsenal DLR opened, people assumed that North Greenwich would become less busy because it was assumed that the masses that took the bus to Woolwich would now take the DLR – how wrong the assumptions were! The buses are now as busy as they were, North Greenwich is far busier than it was and Canning Town has been thrown into that mix as well. I agree with you about Canada Water (having worked there once) – it has become a major hub now, along with a few other what-used-to-be-quiet stations on the Jubilee line extension. With South Eastern being as unreliable as anything these days, we're finding more and more people getting on at London Bridge anyway, and with the Westbound trains equally as rammed from Stratford in the mornings, it's as if nobody seems to work anywhere now apart from Canary Wharf (it's like mass exodus there on a normal day). I'm not holding my breath to see whether Crossrail takes away some of the strain from everyone's journey...

Agreed. Agreed. Agreed.

Having just come back from three weeks of leave and thus missing most of the TBTC 'action' since implementation, I am reasonably impressed that it's not so much of a mess-up now as it was every other time I've worked during TBTC running. Working the evening peak tonight, I was relatively surprised at how one train would depart, and literally 25 seconds later (and yes – I counted using the dot matrix timers) another train had already fully berthed the platform and opened its doors. This happened with three consecutive trains.

I was also surprised on Sunday night, given the system reboot, that we managed to pick up the pace fairly quickly, and by the time The O2 were kicking out the little darlings from the JLS concert, we had a regular-and-to-the-minute 3 minute service on the westbound (yes - the eastbound was a bit ropey, but you can't have it all). 16,000 cleared in under 45 minutes is a record (with the worst part of the evening lasting about 15 minutes – again record, considering 17,000 takes about 1hr to clear, worst part lasting about 25-30 minutes, alcohol dependent).

I too am feeling a little bit encouraged, though to get to a stage like this has taken far too long. There's also several things that worry me – we had a situation with the PEDs some time ago, whereby a door had to be isolated, but the train had no forward movement. Whilst this has been fully investigated and the root cause found, nobody has decided to enlighten us (or anybody else with PEDs for that matter) about what the actual problem was, what caused it and how to prevent it happening in the future. Somebody has also been told (by a duty manager trains) that "you can't isolate a door unless the door is fully closed." Well – what a sweeping statement. Under tripcock operation, if a door was failing to close, failing to open or just any general fault occurring that prevented the PED suite from being proved closed, you could isolate that door. We will always try to ensure the door is shut before isolating (obviously to prevent somebody falling onto the track), but usually, if there's an obstruction that is fully preventing that door from being shut, we would still isolate that door and have a barrier (or the member of staff who has isolated the door) standing in front so that there is no risk to those passing by when the train approaches/departs. Nobody has really explained the whole PED situation at all and I'm now fairly reluctant to even touch the things should it "close the track" (as they're now "in" with the system)... I have chased it up, but I might as well have sent in a Stamped Addressed Envelope...

Yes - the central line has an ATR subsystem which isn't enabled as it tended to show up issues with both the underlying ATS (Automatic Train Supervision) system and also the cab displays which were designed to give "time to depart" at each station (who remembers "spurious "hold" indications?)

Bizarrely, parts of the Piccadilly line have (had?) an early form of Automatic Train Regulation, which was effectively a simply analogue computer. From distant memories of bookwirings, this used a pair of wires running between stations, an arrangement to switch resistors across these wires dependent on train positions, and a comparator unit at some stations which would hold trains dependent on the relative resistance across the pairs of wires ahead and in rear of the station. A "Balance Headways" switch in the control room enabled the system. Does anyone know if this system is still in use?