TBTC Testing

Ah ok, thanks. Apologies. I should have said 'stalled' rather than 'gapped' - as usual some 'Chinese whispers' going on - didn't mean to add to that. Was puzzled about that because more than once Line Controller talked about train stalled on Eastbound between West Ham and Stratford and I was wondering how (and why) on earth it had reversed back Westbound!! I'm glad I'm not the only one who gets west and east muddled up (complicated by the fact that West Ham is geographically slightly east of Stratford).

it certainly does seem odd compared to that different technological world (i.e. investment banking IT) where small iterative changes are generally preferred to big bang changes that transport professionals who have to keep the service running for 20x7 days choose the big bang approach. Whoever it was that signed off the big bang change should have his/her head examined!

I've been checking the TfL website on and off all day and I have no issues to report either!

Sorry to disappoint you, but Signalling Engineers are only human too. The more towards a 'black box' system we go, the harder it is to predict how the system will behave under every possible permutation, and the harder it is to test - which is one of the advantages of a more traditional system, albiet things can still slip through the net and go undiscovered for many years!

At least with a traditional system one can set up conditions and clearly see the effect at each stage, wheras with this you have to rely a lot more on the data validation and end results.
It's got to be at a stage where it can be trusted to perform, or else it wouldn't have been commissioned - but I wouldn't be surprised if some of the quirks of the system are still to be discovered in the next few weeks and months.

Went on the Jubilee line from Westminster to Kilburn today. Certainly feeled a lot faster, no complaints from me.

I have to say, the change in speed is really significant for me. I was getting used to dawdling and an hour commute taking at least an extra 15 mins before Christmas! I made it in just under an hour today, which hasn't happened in a long time!

Help! I have no idea what's happening on the Jubilee Line. All the signals are covered up! I'm a traditional block man so somebody needs to explain what all this TBTC is about....

I have notice quite a long delay at dollis hill in both directions. I guess this is because of the swiching to tbtc.

What will happen in the case of a problem with the TBTC system? Will they remove the old signalling after a few months or years?

Victoria Line's system is based on fixed blocks. TBTC is not.

www.trainweb.org/tubeprune/Victoria%20Line%20ATO.htm

After a couple days' use in the peaks my impression is that the end-to-end journey times are much faster, but that'll be mainly down to the increased capacity allowing full speed to be attained, whereas the rather long blocks resulting from hasty reversion to conventional signalling following the (allegedly) failed Westinghouse system planned for the Extension in 1999 resulted in peak congestion, particularly a.m.

That said, at present the number of trains seems to be considerably short of the maximum – roughly 3-4 minute intervals rather than 2½ previously – although indications are the system will be well able to cope.

However, I did observe notably faster running from St John's Wood down to Baker Street, complete with the pressure wave I haven't perceived in ages.

One downside though – the closure between Stanmore and West Hampstead this Sunday appears to be the last scheduled in the TfL works programme, so if this really is the last then it's farewell to Met trains stopping at Willesden Green, and this may perhaps be the only occasion when S-stock trains call there! Also farewell to a motley variety of vintage buses, including RMs and RMLs, on Jubbly replacements.

Every silver lining has a cloud.

My experience of the last couple of afternoons/evenings has been that I've reached every terminus, meal relief and bookoff point on time or a tad early. I'm not sure that's ever happened to me before on successive days! That is good for everyone.

I must say I find the actual movement of the trains annoying bordering on embarrassing at times. I don't want to appear too precious about driving technique because many passengers probably don't care too much about the lack of a smooth ride. But I would also like to know if there is a way of preventing the 'thermostat' stop-start as the train tries to keep at a target speed. It is particularly jarring when the speed is slow - and the speed is very slow at times as you are effectively being regulated in section rather than in the platform. It's not a bad thing to avoid long platform dwell times but I don't think they've quite got the balance right.

Why are these trains stopping with a pronounced 'jolt' at each station, as if the T/Op had released the 'deadman' too early? It doesn't happen on the Victoria Line, Central Line or DLR? That's why I said the Vic's old system works better.

The jolt can be removed, as in careful car driving, by releasing the brake the millisecond before stasis and then reapplying it once stationary. Perhaps the software can be tweaked to achieve this. Also, the "thermostat" de-accelerate effect is distinctly noticeable to passengers and I hope the software can also be tweaked to alleviate this.

Are all trains using ATO now? All the ones I've travelled on this week appeared to be. Also the service seems to be achieving good regularity now, roughly 3-4 minutes, implying consistent driving.