What next for LU? At full capacity...

[AM9]

Comparing the number of carriages between Thameslink and Crossrail is a bit of a red herring. The Crossrail stock uses longer carriages and the railway itself is far shorter

The core, being a simple through route with flying junctions at each end, all platform edge doors, uniform train lengths, and ATO; would it be possible to raise the peak frequency above 24tph?

 

[glbotu]

The core, being a simple through route with flying junctions at each end, all platform edge doors, uniform train lengths, and ATO; would it be possible to raise the peak frequency above 24tph?

I think they've said there's scope for up to 36tph - 11 car trains. I can't remember where I read that, but I certainly remember it.

 

[matt_world2004]

Maybe where possible whole sections of track should be four tracked to reduce downtime for maintenance and limited stop running.

 

[AM9]

Maybe where possible whole sections of track should be four tracked to reduce downtime for maintenance and limited stop running.

And HP

That would only be affordable on surface streches

 

[Taunton]

These high train rate per hour throughputs are potentially achievable on an end-to-end line, but not so easily where two separate branches converge, as in the case of Crossrail westbound at Whitechapel, because they depend on to-the-second management of headways, which is just not practical where you have two separate branches converging.

If the two branches had been brought in either side of a westbound island platform that does give some benefit to merging the two beyond the station, but as I understand the convergence is a plain one east of the station.

One of the ways performance was improved on the Northern Line at Camden Town was introduction of "straight through" operation in the a.m. peak northbound of the two routes which meet there, rather than the traditional alternating pattern. This with a fully flying set of junctions.

 

[AM9]

These high train rate per hour throughputs are potentially achievable on an end-to-end line, but not so easily where two separate branches converge, as in the case of Crossrail westbound at Whitechapel, because they depend on to-the-second management of headways, which is just not practical where you have two separate branches converging.

If the two branches had been brought in either side of a westbound island platform that does give some benefit to merging the two beyond the station, but as I understand the convergence is a plain one east of the station.

Well they haven't and it will be decades before changes at that level are undertaken especially given the cost of subterranean station building.
If Crossrail is seen to be a significant part of meeting London's commuting needs, more will be built, in much the same way as the Paris RER grew to whay it is now.

One of the ways performance was improved on the Northern Line at Camden Town was introduction of "straight through" operation in the a.m. peak northbound of the two routes which meet there, rather than the traditional alternating pattern. This with a fully flying set of junctions.

There could be 'flighting' arrangements if the timing on one branch slips which wouldn't be a problem if both branches at one end, (say Shenfield and Abbey Wood) had services to both branches at the other end, (Heathrow and Maidenhead/Reading). In that case regular passengers boarding in the core would be used to checking live destination information on the platforms.

 

[rrt1928]

A question from a new member:

Is there any scope for meaningfully enlarging the tunnels on the deep level network (i.e. to something similar to the diameter of the tunnels used by Great Northern trains to/from Moorgate)?

I am aware it would be a very expensive undertaking but if the end result meant you could use larger trains on these lines would this make it worthwhile.

What are the principal obstacles to doing this?

I would be interested to know the thoughts of other contributors.

 

[kjhskj75]

Obvious problem:

The line would have to be taken out of service (for years) while you did it.

Less obvious problem:

In places tunnels have been threaded through very tight gaps between other tunnels. (e.g. Victoria line at King's Cross). Larger tunnels wouldn't be able to squeeze through.

Building completely new lines, even ones parallelling existing lines, is a much better idea.

 

[Haydn1971]

Is there any scope for meaningfully enlarging the tunnels on the deep level network (i.e. to something similar to the diameter of the tunnels used by Great Northern trains to/from Moorgate)

From a civil engineering point of view it's possible but I'd suggest that disruption and access issues would make it cheaper to "simply" build a new line instead. You would either have long sections closed for years to enable widening of the tunnels, the geometry is unlikely to suit longer carriages so some parts would require substantial machine digging instead of the production tunnel boring machine approach, access into construction sites would be a logistical nightmare.

 

[swt_passenger]

I think they've said there's scope for up to 36tph - 11 car trains. I can't remember where I read that, but I certainly remember it.

The highest theoretical service frequencies shown in signalling system details are usually defined as being for short periods of recovery from perturbations (problems), they aren't necessarily feasible continuously.

I think the maximum continuous frequency is 30 tph.

 

[jopsuk]

The core, being a simple through route with flying junctions at each end, all platform edge doors, uniform train lengths, and ATO; would it be possible to raise the peak frequency above 24tph?

run into issues of service patterns and capacity on the branches- especially the GEML. As it is as far as I understand Shenfield will get something like 8tph, with Abbey Wood getting 16tph- but that will mean a 2.5min-5min-2.5min-5min pattern on the branch in order to maintain 2.5min intervals in the core.

 

[Taunton]

As it is as far as I understand Shenfield will get something like 8tph, with Abbey Wood getting 16tph- but that will mean a 2.5min-5min-2.5min-5min pattern on the branch in order to maintain 2.5min intervals in the core.

I hadn't seen that before (source?) but presumably westbound would be done like the Jubilee Line merging the North Greenwich starters into the service, with trains on the Abbey Wood branch at even 3.75 minute intervals, to get even loading at Canary Wharf, and then alternate trains run slow on to Whitechapel to lose 1.25 minutes and slot in behind the Shenfield service.

Eastbound in the morning peak will be more of a problem as you can't do that, and the first of the Abbey Wood pair will tend to overload.

Every 7.5 minutes will seem a bit of a thin service at Stratford in comparison to the Central Line, which might deliver four westbound trains in that time. I hope the cross-platform connection there doesn't get overloaded in the morning peak. In fact, an issue I believe is that in the morning the eastbound major flow will be to Canary Wharf/Abbey Wood, while the major westbound flow will be from Shenfield/Stratford.

 

[D365]

I was fairly sure that the peak service pattern would be 12tph on each of the eastern branches... With a supplementary service on the Shenfield route that will continue to Liverpool Street high-level.

 

[Envy123]

The Northern Line at King's X in the peak is so bad, that I once decided to take GN to Finsbury Park and then to Moorgate and change there so I could get to London Bridge.

I hope there will be new lines which will link King's Cross to places like Old Street and Bank. Otherwise, I have to hope that I work near a mainline station.

 

[baz52]

Hi Dab, just had a look at crossrail site, it says 12 ph plus 4 rush hours I think, its quite usefull.
--- old post above --- --- new post below ---
But less of peak!

 

[jopsuk]

OK, I'll admit I was wrong!

 

[SpacePhoenix]

Would the installation of full ATO on all lines bring about much (if any) increase in capacity?

 

[AM9]

Would the installation of full ATO on all lines bring about much (if any) increase in capacity?

It would probably make it easier to operate consistently at whatever high frequency the timetable was. Very small differences between drivers, trains and passenger behaviour can all combine to disrupt an intensive flow of trains to the point where the timetable breaks down. An ATO system has the greater picture in view and can be programmed to adjust train running as necessary to reduce the impact of or even recover from disruption.

 

[SpacePhoenix]

Before the Jubilee line was converted to full ATO, how much chaos/problems was caused by drivers going to far past the marker boards in the new section, preventing the PEDs from opening?

 

[Domh245]

Before the Jubilee line was converted to full ATO, how much chaos/problems was caused by drivers going to far past the marker boards in the new section, preventing the PEDs from opening?

I believe that was a relative rarity.

The long term plan for LU is to install ATO on all lines, but the problem with any metro system is that there will always be a cut off point where the service simply can't run any more. If you try to run too many trains, the dwell times become too short and people either can't board (defeating the purpose of the system) or they hold the doors, delaying the service. If you make the trains longer, so that people can board easier, it will take longer for trains to pass junctions, PSRs, and clear platforms, limiting headways and thus frequency. Sometimes though, ATO systems do have some slack built into them, for example with the S40 system on the Northern line, the braking rate for outdoors stations is set to a low rate all year, so that they don't have to rewrite the timetable every time the rails get slippy. They could use a slightly more agressive braking rate, but there is still a danger that the service will need rewriting during leaf fall.

 

[AM9]

Before the Jubilee line was converted to full ATO, how much chaos/problems was caused by drivers going to far past the marker boards in the new section, preventing the PEDs from opening?

I was thinking more of:

subtle differences in acceleration and braking rates of different drivers could result in uneven headways
different acceleration capabilities of trains with one or more motor cars locked-out because of faults
random behaviour of passengers exacerbating the above issues, making delayed trains even later as more passengers congregate at stations.​

The last point can be addressed automatically by delaying trains ahead, (as is done manually now when trains are missing). The resonsiveness of an auto system can implement these measures before perturbation in timings are significant enough to create problems at the junction with surface timetables, e.g. Stratford or OOC in the case of Crossrail.
ATO doesn't increase the theoretical maximum frequency, it just makes very short headways easier to maintain.

 

[glbotu]

I was thinking more of:

subtle differences in acceleration and braking rates of different drivers could result in uneven headways
different acceleration capabilities of trains with one or more motor cars locked-out because of faults
random behaviour of passengers exacerbating the above issues, making delayed trains even later as more passengers congregate at stations.​

The last point can be addressed automatically by delaying trains ahead, (as is done manually now when trains are missing). The resonsiveness of an auto system can implement these measures before perturbation in timings are significant enough to create problems at the junction with surface timetables, e.g. Stratford or OOC in the case of Crossrail.
ATO doesn't increase the theoretical maximum frequency, it just makes very short headways easier to maintain.

Indeed, apparently there were frequencies of c. 40 tph through Ludgate Hill in the 1900s. This was definitely achieved without ATO. It was also probably caused huge delays all the time.

 

[cjohnson]

Before the Jubilee line was converted to full ATO, how much chaos/problems was caused by drivers going to far past the marker boards in the new section, preventing the PEDs from opening?

I've been on Jubilee line trains which have overshot by enough to stop the PEDs open; twice in the last couple of months..

 

[talltim]

There presumably becomes a point where the attractions of of working and/or living in London get outweighed by the problems. The transport system being completely full becomes self regulating, if you have too much trouble getting to work, then eventually you will look elsewhere.
What the tipping point for the general population is is anyone's guess.
I personally loved working in Kensington for just over a year, commuting in from Harpenden, but;
A: That was 15 years ago
B: My ticket was paid for
C: I was paid for my travelling time
D: I was younger
Now I'm beginning to get sick of my Chesterfield-Sheffield 20 minute commute and the trains are frequent enough to be turn up and go, are rarely late and I normally get a seat.

 

[SpacePhoenix]

How deep would any new tubeline or "Crossrail 2" line need to be bored to clear everything, eg tube lines, services and utilities, building foundations, etc?

 

[Bald Rick]

How deep would any new tubeline or "Crossrail 2" line need to be bored to clear everything, eg tube lines, services and utilities, building foundations, etc?

Well that depends where it's going. Crossrail 2 is being threaded through a few tight spots, but in some places, eg Tottenham Court Road, it will be the best part of 50 metres below ground level.

Safe to say that there won't be any more lines through Tottenham Court Road after that.

 

[Taunton]

I've been on Jubilee line trains which have overshot by enough to stop the PEDs open; twice in the last couple of months..

I don't recall one issue where in the manual driving days the Jubilee train actually overshot the marks. There were a number of incidents where it was suddenly announced that the doors were not opening and we would now continue to the next station, from where passengers would need to come back, but I understood that these were to do with the train-door interface. These appear to continue, they seem to come and go in waves, and I understand many happen at Westminster, whatever the problem is with the equipment there.

 

[Bald Rick]

I don't recall one issue where in the manual driving days the Jubilee train actually overshot the marks. There were a number of incidents where it was suddenly announced that the doors were not opening and we would now continue to the next station, from where passengers would need to come back, but I understood that these were to do with the train-door interface. These appear to continue, they seem to come and go in waves, and I understand many happen at Westminster, whatever the problem is with the equipment there.

Pre ATO on the Jubilee I reckon I had a 'repositioning' of a train to link to the PED approx every third trip.

Since ATO, I've not had a single occurrence. And I use Westminster almost every day.

 

[Taunton]

I'm guessing the 'repositioning' was driving the train forward a fraction, which was not an issue for the passengers, whereas once past the point of no return it is continue to the next station. Yes I do recall a few of these as well, generally unnoticed by normal passengers, despite living on the JLE all through the manual driving time (1999-2010?). Funny how our experiences differ. I used to be quite surprised at how accurate the manually driven stops typically were.

I think the point about Westminster PED issues came from a past post somewhere here, which coincides with my experiences.

 

[Busaholic]

Apart from what is already being worked on. like Crossrail, Thameslink 2000 and the Northern Line bifurcation to Battersea (grrgh!) nothing of any significance is going to be happening with rail in the Greater London area in the next five years at least, which is why Sir Peter Hendy was warning a few months ago of the potential for civil disorder with a rapidly increasing population desperate to travel to and from work and being frustrated. The only answer a cash-strapped TfL has been able to come up with was an extra 500 buses over that five year period, although even that remains unfunded. In any case, traffic congestion in Outer London and parts of Inner London, combined with more notional 20 mph speed limits and speed humps, is leading to more buses being put on to the road every month just to maintain frequencies: an extra bus on each route would alone take up almost all those extra 500 buses without any palpable difference being seen by the passenger. Lover of buses I may be, but I also recognise they cannot solve all London's coming transport problems, or even a significant part of them.

With Gatwick very likely to be given the go-ahead for a second runway, my thoughts are of a new RER type service from there via East Croydon and a limited number of other stops to Victoria, then via Hyde Park Corner, Marble Arch, Paddington, Cricklewood, Brent Cross to ? Perhaps Thameslink 2100, to be completed by 2200. Gatwick to Heathrow would also be feasible this way.