Northern line TBTC, the right thing to install??

Whilst I am not the most technical person to ask about Signaling systems i dont agree either.
I very much dowbt that TBTC is cheaper to install as with most signaling systems which cost several millions of pounds to install. TBTC does allow manual driving however its more complicated than the central as you have to look at the tod all the time rather than the road ahead. Yet other metro's around the world use TBTC and they are more reliable take Hong Kong MTR which uses TBTC. I much prefer a victoria line signaling system DTG miles better than TBTC how often does the victoria have non communicating trains? A complete mess or managed upgrade, probally a mess! What does everybody else think?

As far as I'm aware the Jubilee and Northern lines were linked during the PPP era and when the upgrade was in the planning stage it was always the intention to give both lines the same upgrade, it's just at the time they didn't know how problematic it was going to be installing it. LU were very critical of the huge numbers of closures but in effect their hands were tied.

If you compare the number of closures for Tube Lines to install the upgrade as opposed to the really relatively few planned for the same system on a much more complicated line, I'd say it was being managed well by LU. So, respectfully, I'd disagree with your 'complete mess' phrase - it's easy to say that but why not wait to say that with some information to back up your point?

Surely they must teach you that in school nowadays?



Now you're basing your experiences based on a computer sim - I'm not being funny but I'm sure the people who work for LU must love hearing a 14 year old's negative comments based on playing with some trains on a screen. You're dealing with a lot of clever people who work for LU on here - please try to lift your comments above the banal and uninformed.

Probably a once or twice a week, though as the blocks and signalling areas on the Vic are pretty small, the impact of a train loosing communications is not so great, so you don't notice it.



Which is exactly why, on a high capacity railway, ATO is the way to go. This is not a go at train operators, but proven studies show that an average human will make such a mistake (such as invoking the ATP) whilst doing a repetitive manual task which they are trained to do in the region of once every hundred or once every thousand attempts. A well developed ATO would make the same mistake in the order of once every 100,000 or more attempts.

This is not withstanding the consistency improvements whilst driving between stations. Where an ATO can be consistent to within a second on a interstation run, train operators would struggle to be within 3 or 4 seconds. And don't forget, the closer that you try to get train operators to drive to the limit (i.e. not defensive driving), the more frequently mistakes will be made.

I too am getting a little tired of every other thread here being:
Trains should be driven manually
Trains should be able to go faster etc.

The decisions for line upgrades being as they are are all backed by well reasoned engineering decisions, with things such as future capacity increases in mind. Unless you have facts and reasoning to back up your theories, please don't state them.

"The decisions for line upgrades being as they are are all backed by well reasoned engineering decisions, with things such as future capacity increases in mind. Unless you have facts and reasoning to back up your theories, please don't state them."

So why was the jubilee line such a foul-up?
Why is it still not delivering?
Why is work being done on the northern line until the jubilee line is proven to be working robustly?
What actual steps have been taken to prevent the same foul-ups occurring?
What additional resources are being deployed?

Decisions of this nature are rarely made for pure engineering reasons - and even if they are, the question asked of the engineering team may not be the right ones.

As an interesting metric on the jubilee line - how many train services have been lost to possesions/unscheduled failures etc related to the conversion? How many additional train services have *actually* been delivered since it started operating? How long until the latter is greater than the former?

Not working for London Underground or on the Jubilee Line project, I wouldn't like to theorise as to the real answers to the questions above. I would imagine one factor was that the original contract was let by Tubelines, who were then bought back in house, causing management/contractual transfer issues.

The tender process would have included a technical specification of some sort, which potential bidders would have responded to, and been scored against, along with other factors such as price. The people judging the tender process must have considered that Thales offered the best technical solution against the technical specifcation for the best cost (best value for money). It therefore must have been sold as being the correct solution for the job.

I get the impression most of the people who yarn on and on about manual driving are luddites who'd prefer the tube to still be running on steam... or at the very least would love it if the 67ts and A stock were still creaking along the rails... sigh. Some people hate progress.

I don't think the idea of TBTC is necessarily a terrible one, though the centralization of everything does make disastrous failures that take out the whole line more likely. But there are definitely a few weak points in the design of the current TBTC system, Seltrac. One problem is that the while the the system as a whole is mostly reliable, it's not quite reliable enough, and when it fails, there's not much that can be done.
I think it's instructive to look at how other metro systems around the world operate. The Moscow Metro has considerably more ridershi than the Tube, and higher service levels on its lines, with a peak service of 39 tph. There are a variety of signalling systems on the various lines, randing from 3-aspect colour light signal with train stops, not unlike what can be found in NYC to an ATP system that's like a simpler version of the Central Line ATP. But the principle is that there is always redundancy. On ATP-equipped lines, there are also traditional signals with train stops, so that a train with an ATP failure can keep going. On newer lines, there are no train stops, but there is an independent backup system that uses track circuit codes transmitted in the "wrong" direction along the track and picked up by the rear end of the train. So if both the primary and backup ATP receivers on the front of the train fail, then there's always the possibility of using the backup equipment in the rear of the train. Note that the track is considerably less likely to break than a cable, and if it doesn, it's not like the train can get very far anyway. But if even the backup system fails, the lines still have colour light signals that can be switched on (they're normally used for engineering trains and the like) and the train can continue, at somewhat reduced speed and with a second person in the cab, to the nearest siding.

What a question! If you are a member of this forum surely you by now MUST understand that ALL railway systems are designed to be fail-safe, and have been for the last 130-or-so years (they weren't always before that).

Have you never heard of backups, and backups-to-backups? Or is your laptop flying by the seatofthepants if anything goes wrong?

A lot of response is now controlled by an intermediate layer of software aboard the train, IIUIC? The benefit of this is that as experience and miles are gained, the software can be tweaked to respond better to the environment it reads. It could well be that once the olympics and 2012 are over there will be more time to devote to improving traction control software.

I wonder whether the Jubilee, though, is concentrating on just getting it to work atall in time for the olympics!

The most complicated location on the Northern Line is Golders Green, also Morden and in some ways Finchley Central.

Camden Town is not complicated at all from a signalling point of view. Although the tunnel layout may be complicated, once you realise that the site is actually 3x separate layouts - the northbound junctions, the southbound junctions, and a simple trailing crossover at Mornington Crescent, it becomes easy. The current signalling has 3x IMRs reflecting exactly this layout, albeit all coded 'E' and controlled from the same desk at Cobourg Street.

The Northern Line is basically reliable because the trains have reached maturity (the point where they are bedded in, depot staff are familiar with them, and operating staff know them well), and in the last few years Tube Lines really have got hold of the maintenance for signalling and track. It really is true to say that the biggest cause of problems on the Northern Line is generally passenger incidents in one form or another.

The line also runs well because the current timetable (WTT53) is generally recoverable and has generous running times Mondays to Fridays. A legacy from a certain Mr Millard when he was General Manager.

I am sure the Northern line used to be called the "misery line" I know on the old ITV the tube series used to mention the Northern line allot.
Today I would say the Jubilee line is the offical " Misery line" of recent times! However the tube was filmed around 2002-2005 so quite a while back.

When a delay is ascribed to "signal failure" this actually (normally) means "some part of the signalling system", the bulbs in the signal head are only one small part of this system - indeed I think they're one of the most reliable parts (but am happy to be corrected on this). Also at fault could be track circuits, train stops, point detection, detection of what signal aspect is displayed, and many other things (I can't remember whether point motor and/or tunnel telephone system faults get called "signal failure" or something else).