Can Power be uped on TBTC?

Mod Comment.

Play nicely, please.



What exactly do you mean by 'power' in this context? That dissipated by the braking system because the train is moving faster?

Would it be better to say speed? After all, I think jardine01 is referring to the power increases on the Victoria enabled by the departure of the 67TS and (in effect) the 09TS being able to accept 'load shedding' and regenerated power.

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Wrong; at least in the case of the Central. I won't comment (yet!) on the Victoria, because there are things that I would like to check before commenting. If your statement were true then Wood Lane wouldn't be loaded up with timetables (both global and locally updated) and run on purely deterministic logic.



I'm afraid you are also wrong here - if you can avail yourself of an old WTT for each of the lines, look carefully at the stand times: you may want to concentrate on Hainault, North Acton, Newbury Park, Leytonstone, White City; Seven Sisters and Victoria. That's without factoring in run time variations.



Not because of how the trains are told to run by the signalling system, but because of how they are told to wait by the signalling system - a subtle, yet important difference.

While yes they do always drive to the target speed no matter what, semi-automatic signals along the route are timetabled, so trains roughly stay on time.

The Jubilee sure feels like it drives like that even with a scheduled 5 min gap if it is on time it seems to take it easy.

I have done Canary Wharf to Canada water a few weeks ago It was fast leaving Canary wharf then it slowed down and a constant speed of about 35-40mph all the way to Canada water. On the whole the Jubilee line is slightly faster with the new timetable. By the way does anybody know the line speed between Canada water to Canary wharf?

Ok people, hopefully we can put this one to bed.

I have sifted through all of the literature that was issued to us in Service Control, and nowhere does it mention "slowing trains down to lose/keep to time between stations."

The whole TBTC system is concentrated about maximising line capacity by being able to "automatically" control each train. The speed of each train is governed by several factors, including the current line speed, the distance of the train ahead, approaches to stations and/or crossovers, temporary speed restrictions, etc.etc. Thus by being able to control the speed accurately, trains are able to be run at much closer distances, which means more trains can be run on each section of line.

If you have done a section of line at xx speed, and yet another day did it at yy speed, it has nothing whatsoever with timekeeping, but is related to the other factors which can lead to speed reduction or, indeed, increase.

The control "loops" which form the track-based communication control with each train are purely a modern method of signalling - that is they communicate how far ahead of each train the line is clear. There is no capacity within the loops to tell a train it is running early or late with regard to the timetable. Regulation is done in controlled areas along the line, with the use of platform station starters.

Of course, should anyone have information to the contrary I would be very interested to see it, as indeed some of my colleagues would.

As you are so convinced that something else is occuring, then on my return to work this week I'll do further digging, and ask my Jubilee colleagues. I am nights so bear with me.

But, I'll say again, that based on what I have infront of me, the railway is regulated at stations, and any slower running between stations is not to lose time, but is because of a factor related to the state of the line ahead (another train, restriction, crossover, station etc.)

www.tsd.org/cbtc/Suppliers/Alcatel/SelTracBrochure.pdf

The facility does exist within SelTrac S40 for both methods of service regulation mentioned here.

I've just spent the last month commuting using the Jubilee most days and I can honestly say I haven't noticed any holding in platforms, other than for things like PEA activations. Got me curious now, so I shall hold fire until you've done your digging!

Yes.




Not braking - motoring. At least in my experience - admittedly I am aware where the track objects, axlecounters, and loop boundaries are on a couple of specific bits of the Jubilly:




Yes, you do!

It is also my understanding through a completely separate route to MetControl:



that MetControl is correct - I believe the operative phrase is 'manual destinations' - the Jubilly as I understand it is based on logical block, rather than moving block - if it were set up for moving block there would not be the 'pseudo-station' zones, nor so few defined 'intermediate stopping points'. Granted the system appears to have enough safety distances, conflict zones and velocity restrictions to allow moving block, but AIUI it is just logical block at present, therefore the timing regulation is between fixed locations ie stations or other dedicated stopping locations and not between the 'envelopes' of moving trains.

Really I wish the 1996 stock was 100% motor axled that would really give power a boost and that would cut journey times even more. I was on the Jubilee yesterday what i cant understand is Green Park to Bond street seems slower Northbound. But on the Southbound between Bond street and Green Park is hell for leather! Why is this?

I dont think it is gradient. as speed should be the same on the Northbound and Southbound tracks.

Whats the line speed through Bond street to Green Park? it is a pritty fast strech. Even under the old signaling system it was still fast along there.

I know what you mean its a bit strange under tripcock signaling it was 25mph then when you pass the curve there is a T sign which means trains can go up to line speed 60mph. Why is it in TBTC there is no 25mph speed restriction?

One driver told me the Jubilee line line speed is 60mph but do trains actually reach this speed? on the GPS a few years ago i recorded 58mph betweeen Wembely Park and Neasden.

Quite different from the actual route. I've been struggling to try and reconcile what you've said with the previous version.



Are you sure about that? My notes mention 1987 by whict time the '38TS were long gone.