Why cant TBTC stay at a constant speed??

From what I understand the same Jubbly TBTC signalling is currently being installed on The Northern. Expect guided tours on foot of Spaghetti Camden Town Junction and the rest of it in the not so distant future. It could become a tourist attraction in it's own right with LU making a fortune out of it. All it takes is a little forethought to make the best out of bad ideas.............

Blimey - Here's a girl taking a gamble............

www.thisislondon.co.uk/news/celebritynews/rb-on-the-jubilee-rihanna-and-entourage-take-the-tube-to-rap-gig-at-the-o2-7594275.html

For sure, I agree.

As a software engineer though, I'd be wanting to control the throttle with more control than just on/off...

To give the current software the benefit of the doubt, it's unlikely that the developers of it would have wanted the train to lurch forwards and backwards. Therefore, I think there's a good chance that the interface between the software and the traction units doesn't support variable control fully.

The clever algorithms that you mention could only apply if the whole system supports variable control, rather than just parts..

We were very quick between Green Park and Westminster, with sudden heavy braking then high rates of re-acceleration, but between Waterloo and London Bridge, it was crawling along with sudden jerks of acceleration followed by coasting. I don't know how close in front the next train was.

I feel I need to mention the rough stops on the new Vic system when the train comes to a standstill in a platform or such. It would probably be very simple to program it to stop smoothly without it feeling like one might get whiplash. It can be done on manual lines by drivers who bother so why not on the ATC lines?

The usual excuse for ATO is that drivers cannot brake as efficiently as the computer. On some lines over in Japan they use ATC which is like Central line coded manual but I think it may be moving block. Basicly they follow target speeds set by the ATC system. Drivers are trained very thoroughly, to a set technique (by the looks of it) and to drive as efficiently as possible.

I think this is the way forward rather than going completely driverless (puts people out of work) or just simply ATO which seems almost pointless to even have a driver until somthing goes wrong. Everyone wins near enough!

Nonsense.

Talking about the Jubilee a good driver will get close to the ATO run profile but an average driver will be way out - not only does that not optimise the line capacity but it also means variability in run times between different trains which causes uneven loadings and further delay.

Under ATO trains are getting to a faster speed more quickly and they are using the full traction capability in a way that wasn't possible pre TBTC.

You can certainly say that the ATO profiles could be adjusted to reduce the effect of the on / off acceleration but at the expense of line capacity but to say that ATC will give a better result to customer journey time than ATO is just incorrect.

I have to agree with jango's comments above about the "extreme' comments. As someone with next to zero technical knowledge about the tube it is clear that the (long-awaited) signalling system and timetable upgrade still has to bed-in. It will also probably also take some time to tweak the timetable to optimise the (impressive) capability of the 95ts and the abilities of the new signalling system. A lot of people here also seem to be comparing the Jub to the Central. Even that line, as I understand, had a difficult transition to the present system.

I used the Jubilee last week and while there were sections on which the on/off ride was annoying, I could also appreciate that on certain sections, eg Finchley Rd-Neasden the performance was better than ever. On a few occasions my train even caught and outran a fast Met, which is always satisfying.

Some more advanced ATO systems such as Seltrac have have different ATO driving strategy options for energy efficiency. The most energy efficient strategy is to power up to maximum target speed and then coast back to minimum target speed. A larger target speed range = more energy efficiency, with only minor increases to journey time, but creates the on/off ride that many train spotters seem to dislike.

Whether or not "train spotters" dislike the ride, actually it is recognised bad practice within the industry.

If a Train Operator routinely drove a train in this way, it would be raised either by their instructor during training, or by a manager during the scheduled assessments, on the basis that it creates an uncomfortable ride, as well as placing additional wear & tear on the train.

I can understand applying power to maintain line speed, or applying brakes to limit to line speed, but it is simply crazy to have a lower speed enforced in this way simply because the train is running early. If the train is running early and is on a downhill section of line, for example, it should be allowed to coast up to line speed and if necessary dwell for extra time in the next platform.

Whilst the stopping accuracy of TBTC is undoubtedly good, the system still manages to stop with a very pronounced jolt, which the 67 and 92 stocks both managed/manage to avoid. Again, stopping smoothly is something which is emphasised during training, and followed up during driving assessments. This is something which can and does generate customer complaints, as well as potentially creating a lot of work for the company if a customer falls over and becomes injured.

Room for improvement!

Well, the new timetable has been in for almost a week. There's very little 'slack' - it is much more difficult to make up time and there are bound to be more late meal reliefs and overtime slips submitted. Nevertheless, I'm happy because at long last speeds into platforms on the open sections have been ramped up (generally from 22 mph on entry to 30). Makes a huge psychological difference I reckon both to drivers and to regular users of the Stanmore to Finchley Rd part of the line.

I don't like ATO and I miss driving the train. I do understand the benefits of the system and the above improvements are going to make it more tolerable. I just think for the expense it should be a hell of a lot better and the way the trains are being driven puts so much extra wear and tear on them.

Nope, this is different to station approach coasting. There used to be a good article about this on Alcatel's website before their signalling arm was sold to Thales. I'll see if I can find it.



As I'm now living in Australia, I don't get to ride the Jubilee Line that often. However the journeys I took last year, the ride quality seemed to be far better than many other metro lines (numbering 50+) with ATO that I've ridden. The ride quality was also a lot smoother than many examples of manual driving I've experienced. Maybe I rode the Jubilee on a good day?

I don't tend to post much on this forum now, mainly just read. However, these constant anti-ATO threads are getting extremely tiring! I'm sure I'm not the only person who sighs every time there s a "why can't drivers drive in CM on Sundays", or "are the trains running at full power yet" thread.

ATO with continuous ATP has an excellent safety record (outside of Washington DC) compared to manual driving and intermittent ATP such as train stops. Thus virtually all new metro lines and signalling replacements in the future (around the world) will use ATO with continuous ATP as the safety case is far far better. If you don't like it, then tough luck!

"I still think we are some way off before we have trains without a drivers cab." – Pardon me, it seems to be often overlooked, but London already has an extensive system of driverless trains, the DLR! Considerably bigger than many entire urban metro systems, the DLR comprises six branches totalling 31 km with 45 stations, running at up to 2-minute headways with speeds of up 62 kph, carrying over 60 million passengers annually, entirely with driverless trains!

That is not to say the trains are unmanned. Every train has a "train captain" who monitors entry, exit and behaviour, sometimes checks tickets and can operate the train from a console at either end – there are no cabs, passengers can sit right at the front with superb views of Docklands. Or indeed of tunnels – at Bank and between Island Gardens and Greenwich, with three stations in tunnels.

As a prototype for Boris's "driverless" future (again, not intending as I understand it that the trains be entirely unmanned), one need look no further. There are of course also entirely unmanned systems, as short-hop airport transits; though some of these around the world run considerable distances with several stops. I suppose the ambience of such is perceived as safer than general urban systems.

I'm aware of the DLR but it was purpose built from scratch to be automated. Trains run at a maximum of 50 mph (80 kph). It also has emergency walkways where it does go underground. I can't imagine a line like the Jubilee or Victoria or Central going cabless any time soon. Also consider that the 'train captains' are on 37k, only 7k behind a tube driver.

Wolmar's article was just fluff. A complete waste of time - his writing it and ours reading it.