NB signals covered up for testing

[Deleted]

I noticed this weekend that all the NB Jubilee line signals had been covered up so their aspects could not be seen for my journeys between Willesden Green and Finchley Rd on the Met.

I was wondering what the nature of the testing was that required this as it must have taken a while to cover up all those signal heads

If the trains were ATO running I would have thought it wouldn't matter if the legacy fixed block signals were visible to the T/Op or not.

[memorex]

Just a guess, but surely if your train passes a red aspect on a signal relating to the line you are travelling on, it's a SPAD?

[Chris M]

Presumably though if your train is travelling in ATO, you have authorisation to pass the lineside signals at danger?

[Tubeboy]

The whole line is shut for ATO testing 2-5th April. The tripcocks are being cut out, have seen a few trains go through reds. In this instance they wouldnt be classified as SPADS, and they would have prior approval.

[21146]

Are they running in ATO on test or, rather, in "distance to go" manual driving which is different?

[Tubeboy]

AFAIK its ATO.

[Deleted]

This weekend has been about Train Operator familiarisation.
There were a number of trips made In PM (protected Manual) mode where the T/op drives to a "Target Speed" and "distance to go".
All went fairly well but the system Is not ready to go live just yet (too many niggly faults) and no there was no ATO running this weekend.

[Tubeboy]

Thanks for that

[version3point1]

There was no ATO and those in charge did their best to encourage those on the handle that the system could be relied upon to some extent – they even went as far as pulling the blinds all the way down to get them used to looking down at the Train Operators' Display as opposed to looking for signals. They'd also taken the limiters off the motors so some trains were apparently racking up a bit more speed than usual. As expected, there's a few problems with the PEDs and not getting Accurate Stop. Relying on just the TOD to bring the train to a stop means the train has overrun by a whole metre in some places. (The PEDs allow some margin for error, but not by that much!) Also, the Ready To Depart Indicators are allegedly supposed illuminate once the Train Operator has received his target speed, thus allowing the SA to then raise the SATS bat as and when, but the RTDI has also been illuminating when the TOD shows 'HOLD', so effectively it's like raising the bat when the repeater's showing amber and looking like a right numpty for a good couple of seconds.

It's still not enough to feel like these relentless weekend closures are worth it though.

[Deleted]

I notice that the signals are covered up again today and I enjoyed watching a train with its tripcock cut out accelerate away through the raised trainstop for the Finchley Rd SB starter....

I hope no-one minds me asking - how has the testing been going this weekend compared to back in April?

[Deleted]

Saturday was not that successful. Sunday was much better.

[Deleted]

Jun 14, 2010 21:59:33 GMT @peddoors said:

Saturday was not that successful. Sunday was much better.

How much of the line is able to be run under ATO these days?

[plasmid]

Moving Block ATO is a waste of time in my opinion...too advanced for this point in time with far too many "teething" issues as mentioned above.

From what I've heard around this forum (somewhere in the depths) is that Fixed Block ATO is just as good and can run just as many trains per hour as Moving Block ATO.

Would it not have been cheaper and easier to install Fixed Block such as that on the Victoria/Central Lines?

Victoria Line utilises Fixed Block yet only has 2 platforms at each end of the line to turn trains around in (minus the few that terminate early at Seven Sisters). The Jubilee will have 3 platforms to turn trains around in.

Whilst (looking on YouTube) at the other systems around the world that use the same Moving Block system, I can say that it works well. But then, so does Fixed Block...

As I say...too advanced too early.

[tubeprune]

Jun 15, 2010 11:35:18 GMT plasmid said:

Moving Block ATO is a waste of time in my opinion...too advanced for this point in time with far too many "teething" issues as mentioned above.

From what I've heard around this forum (somewhere in the depths) is that Fixed Block ATO is just as good and can run just as many trains per hour as Moving Block ATO.

Would it not have been cheaper and easier to install Fixed Block such as that on the Victoria/Central Lines?

Victoria Line utilises Fixed Block yet only has 2 platforms at each end of the line to turn trains around in (minus the few that terminate early at Seven Sisters). The Jubilee will have 3 platforms to turn trains around in.

Whilst (looking on YouTube) at the other systems around the world that use the same Moving Block system, I can say that it works well. But then, so does Fixed Block...

As I say...too advanced too early.

If I might chuck in a few comments about this:

ATO - automatic driving that is - does improve performance and allows more trains to be run over a manual system, even if nothing else changes. For example, if you improve the braking rate into stations by just 0.1m/s/s, you can get an extra train per hour through the line. The average driver, driving manually, won't get much better than 0.7m/s/s, whereas a modern train on ATO will get 1m/s/s. Even the 67TS gets 0.9m/s/s and a smooth stop with the new NADB.

You are right to be concerned about terminal operation. Brixton is the pinch point on the Victoria Line and effectively restricts the throughput to 28.5 trains per hour. Having an efficient point layout with sectional release is essential. Dwell time at busy stations will also restrict throughput. Any more than 40s wheel stop to wheel start is death to a 2 minute headway.

As for moving block, I would question the assertion that the Thales S40 system is true moving block. If you have a system with a fixed, track-based loop, crossing every 25 metres to provide location updates, it's hardly moving, is it? It's more like "very short fixed block". Leaving that argument aside, it is a mature system though. It's been around for over 20 years in one form or another and it works. The problem is that its previous installations have almost always been on new railways, not overlays as they're doing on LU. That's where the trouble lies - trying to put new wine into old bottles.

[plasmid]

With regards to the Victoria Line. Would it not be a good idea to have 4 extra drivers. 2 at Brixton and 2 at Walthamstow Central.

This way when the train comes in, the spare driver is ready and waiting to take over the train at the other end of the platform. So when the driver comes in all he has to do effectively is open the doors, release control and get out the train whilst the other driver gets in and takes control over.

This would cure a lot of the dwell time it takes for the driver to switch cab ends.

With regards to the ATO it does work well however it gets messy with the inevitable Passenger Emergency Alarm. Every other morning on the Central Line without fail, ruins the service.

And with regards to the Thales S40 system...if they knew there were going to be issues installing such a system on a line with existing infrastructure then perhaps I should hint at Bombardier and the Victoria Line and Fixed block.

[Deleted]

Jun 16, 2010 12:55:49 GMT plasmid said:

With regards to the Victoria Line. Would it not be a good idea to have 4 extra drivers. 2 at Brixton and 2 at Walthamstow Central.

This way when the train comes in, the spare driver is ready and waiting to take over the train at the other end of the platform. So when the driver comes in all he has to do effectively is open the doors, release control and get out the train whilst the other driver gets in and takes control over.

This would cure a lot of the dwell time it takes for the driver to switch cab ends.

Stepping back is indeed effective, but when something goes wrong and trains come in the wrong order you have a problem - imagine the driver that's supposed to take your train is behind you, and can't come in to the station because both platforms are taken.

[mrfs42]

*to get back to the Jubilee Line*

The need for stepping back can be mitigated by the Thales S(whatever) short fixed blocks - these permit a relatively higher approach speed when closing into the station throat at Stratford or Stanmore.

Yes; the third platform allows a greater theoretical capacity, and some breathing space if you have a train sat down in one of the platforms.

It will all revolve around the magic 4 minutes - in/out/shake-it-all-about, terminal stand time cannot be directly compared between the Vic. and the Jubilee; of course these days you've got to factor in the sloooooooow electric points too!

[DWS]

Points at Stratford are air operated

It will all revolve around the magic 4 minutes - in/out/shake-it-all-about, terminal stand time cannot be directly compared between the Vic. and the Jubilee; of course these days you've got to factor in the sloooooooow electric points too![/quote]

[harlesden]

Apr 12, 2010 1:40:29 GMT version3point1 said:

 they even went as far as pulling the blinds all the way down to get them used to looking down at the Train Operators' Display as opposed to looking for signals.

Surely a rather scary experience for even the most experienced driver.

[Deleted]

Jun 16, 2010 12:55:49 GMT plasmid said:

With regards to the Victoria Line. Would it not be a good idea to have 4 extra drivers. 2 at Brixton and 2 at Walthamstow Central.

This way when the train comes in, the spare driver is ready and waiting to take over the train at the other end of the platform. So when the driver comes in all he has to do effectively is open the doors, release control and get out the train whilst the other driver gets in and takes control over.

This would cure a lot of the dwell time it takes for the driver to switch cab ends.

With regards to the ATO it does work well however it gets messy with the inevitable Passenger Emergency Alarm. Every other morning on the Central Line without fail, ruins the service.

And with regards to the Thales S40 system...if they knew there were going to be issues installing such a system on a line with existing infrastructure then perhaps I should hint at Bombardier and the Victoria Line and Fixed block.

What you are describing is stepping back, which already takes place on the Victoria Line. The dwell times at Brixton are still restricted by the crossover (i.e a train in the SB platform has to wait for a train to depart and arrive in the NB platform before it can depart.)

Your opinions of Thales S40 seem very negative. It is the most mature and commercially successful "moving block" signalling system available. Moving block signalling can have platform re-occupation times approx 10-20 secs better than fixed block ATO signalling - thats quite a few extra tph! Paris Line 14 (Siemens moving block) has platform re-occupation times of 40secs!

[plasmid]

My point comes down to what is really needed.

Do the passenger frequency levels really require a more sophisticated moving block ATO system or would fixed block like on the Central/Victoria not be adequate enough.

Also add in costs - which type of system would be cheaper?

[Chris M]

would you rather have a system that is adequate for now or one that has the capacity required for the foreseeable future? If you choose option 1 then you must accept further disruption as the system is replaced within a decade.
It isn't just about which is cheapest but which gives the best value over the lifetime of the assets.

[Deleted]

Jun 19, 2010 20:18:31 GMT plasmid said:

My point comes down to what is really needed.

Do the passenger frequency levels really require a more sophisticated moving block ATO system or would fixed block like on the Central/Victoria not be adequate enough.

Also add in costs - which type of system would be cheaper?

A true moving block signalling system would help at station bottlenecks such as Victoria. However, it wouldn't really help at the bottleneck that is Brixton's crossover.

The claimed 33tph seems quite optimistic. Improved train performance will take off many seconds from the current 96sec platform re-occupation time. I am interested to know if any additional signalling features have/will be added at Brixton to speed up movements - such as sectional release (i.e. train departing from NB platform releases 9a points before it's cleared 8b), or operation procedures where doors can be closed just in advance of the scheduled departure time, rather than after the green signal.