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SSR resignalling

Ethano92

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I rode an s7 for the first time under the new signalling system between Latimer road and shepherds Bush market today and was wondering why there isn't any traction motor sound (I think that's what it is, the high pitch sound) when decelerating under this signalling system. I didn't realise the signalling could affect this. The sound occured as usual when accelerating, just not the other way. They appear to be silent pulling into stations. Could anyone explain or refer me to previous explanations? Many thanks.

The braking was of course very smooth and stations are very close on that section but the train also seemed to break much further in advance than with the old system.
 
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Mojo

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I think it’s the difference between friction only braking and dynamic (ie. regenerative/rheostatic) braking.
 

bramling

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I rode an s7 for the first time under the new signalling system between Latimer road and shepherds Bush market today and was wondering why there isn't any traction motor sound (I think that's what it is, the high pitch sound) when decelerating under this signalling system. I didn't realise the signalling could affect this. The sound occured as usual when accelerating, just not the other way. They appear to be silent pulling into stations. Could anyone explain or refer me to previous explanations? Many thanks.

They have had issues on the Northern Line with the brake blocks wearing in a particular way, which is being put down to the ATO. This came to light when they were attempting to uplift top speed from 50 mph to 60 mph. Due to this and possibly other issues 60 mph hasn't yet been achieved on the Northern Line. Hence, the SSR's system has had a tweak made to it that occasional stops are done on friction brake only, which is an attempt to address the possibility of brake glazing.

the train also seemed to break much further in advance than with the old system.

Welcome to Seltrac!
 

Ethano92

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Thanks for both replies. Pretty interesting

Just how useful is regenerative braking if they'll so readily dismiss it? From a moral/environmental standpoint is it very significant. I'm guessing it really isn't very important.

I'm also guessing they'll use friction braking for stops nearer together when they need to slow down from lower speeds then?
 

edwin_m

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Regenerative braking ought to be able to save 20% or more of traction energy on a stop-start duty like the Underground, and also reduce tunnel heating (obviously not an issue on the current section or probably on the rest of SSL either). With DC motors it was necessary to blend in friction brakes at about 10mph because regeneration became less effective, but AC motors can regenerate virtually to a stop. Brake pad replacement is also one of the major maintenance items when friction braking is used routinely. So maybe not an issue if say 1 stop in 20 has to be made on friction, though even then it's wasting 1% of the electricity...
 

bramling

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Thanks for both replies. Pretty interesting

Just how useful is regenerative braking if they'll so readily dismiss it? From a moral/environmental standpoint is it very significant. I'm guessing it really isn't very important.

From an avoidance of generating heat standpoint, it's very significant indeed - although this is more of an issue on the Tube lines than the sub-surface ones. From a financial point of view it's a "nice to have" rather than an essential, however there remains the issue that friction braking costs money in terms of brake wear, as well as incurring extra maintenance time.

I'm also guessing they'll use friction braking for stops nearer together when they need to slow down from lower speeds then?

Can't answer that one.
 
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simple simon

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I've made a video about the automation of the SSR, showing some of SMA 0.5 in action plus looking at other related topics - including the routes that will have 'interoperable' signalling so that automated and human driven trains can still travel along the same tracks without the latter having any special equipment fitted.

 

sharpley

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Very slightly off topic, As the above video mentions, old signals are covered when the new system goes live. I've noticed on the Jubilee and Northern lines that the old signals have been covered but still in place, even after being obsolete for a few years now. I assume removal of the old signalling system equipment isn't part of the upgrade project? Or just isn't a priority to remove.
 

tomglazed

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Took my first ride on the automated section on the circle and H&C lines last weekend. Two things I found odd after observing a few trains at Wood Lane: quite a few trains seemingly took longer but varying lengths of time to open the doors (some around 3-4 seconds) and whilst trains were parked you can hear the brakes releasing/adjusting pressure quite regularly.
 

Dstock7080

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I assume removal of the old signalling system equipment isn't part of the upgrade project? Or just isn't a priority to remove.
The installation team are not tasked with removal of legacy signalling, it will probably remain as on the other Lines.

and whilst trains were parked you can hear the brakes releasing/adjusting pressure quite regularly.
At the boundary point of Latimer Road while the train and system communicate there will be several brake releases.
 

simple simon

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This message has just appeared on a railgen email list ... I wonder whats up?

Unfortunately, more software issues have come up so won't be commissioning until further notice.
 

ijmad

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I heard there'd been some issues during the test on Sat/Sun - I guess they were on the more severe end of things.
 

bluegoblin7

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I’m sure those of us who are directly affected by the work will post as soon as anything is confirmed officially. As far as I’m aware Edgware Road cabin is still closing at the end of traffic on August 9; I’ll be the penultimate signaller.

The main issue I’m aware of over the weekend was an axle counter block failure at Baker Street on Saturday. Inconvenient, but this is also the first opportunity to actually try these with any sort of proper service, and respond to their failure. Teething problems on a project of this scale are to be expected.
 

Dstock7080

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I heard there'd been some issues during the test on Sat/Sun - I guess they were on the more severe end of things.
I’m sure those of us who are directly affected by the work will post as soon as anything is confirmed officially. As far as I’m aware Edgware Road cabin is still closing at the end of traffic on August 9; I’ll be the penultimate signaller.
Now officially delayed until weekend 31 August/1 September.
 

ijmad

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The folks on DistrictDave's forum say it's going ahead!
 

bluegoblin7

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Yes, all systems go for commissioning this weekend. Edgware Road Signal Cabin OP and part of Baker Street Signalling Control Centre (Finchley Road southbound to Euston Square) will close once services finish Friday night.

Test running on Saturday and Sunday, with an expectation passenger services may commence Sunday (as with the commissioning of Hammersmith) if all is going to plan.

As noted elsewhere, the Met will be running a reduced service next week in conjunction with the commissioning.
 

bionic

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What's the general feeling among operational staff about the spread of ATO? Do people like ATO? De-skilling is inevitable.

Once the SSR is entirely ATO and the magic over 50% ATO mark is reached (combine-wide), the firm were planning to change the job descriptions in the train operator grade, alter working agreements and bring in rest day working and reserve automatic train operators in admin roles (presumably to break strikes). Do previously skilled driving and signalling staff seem bothered by that spectre hanging over them?
 

bramling

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What's the general feeling among operational staff about the spread of ATO? Do people like ATO? De-skilling is inevitable.

Once the SSR is entirely ATO and the magic over 50% ATO mark is reached (combine-wide), the firm were planning to change the job descriptions in the train operator grade, alter working agreements and bring in rest day working and reserve automatic train operators in admin roles (presumably to break strikes). Do previously skilled driving and signalling staff seem bothered by that spectre hanging over them?

For signalling staff I’d say the new order is just as skilled. For TBTC the signal desk training just to familiarise with the system is a cool seven weeks in the classroom and on the simulator, that’s before being let loose on a real desk. If anything it’s a bit more “skilled” as there’s quite a few systems issues to learn and be familiar with, and things that the signalman didn’t do before like implement temporary speed restrictions, remotely resolve issues with the on-train signalling equipment, et cetera.

Things may have moved on from having to move levers for every train movement or having to keep on top of what programme machines are doing, however the signalman is still a busy person when the service isn’t perfectly as per the timetable. The Thales product is rather “rough round the edges” so there’s a lot for the signalman to do to keep things running seamlessly, things that others wouldn’t and shouldn’t notice when they’re being done but will notice through a lumpy service when a signalman doesn’t bother to keep an eye on what the system is doing.

Indeed, some of the new rooms have suffered slightly (IMO) from focussing heavily on training line controllers, whilst at the same time giving only lip service to the art of signalling trains, and leaving much skill and knowledge to pass on simply through experience and word of mouth. At some locations there is a marked difference between an “off the street” direct recruit, an experienced ex controller who now also does signalling (perhaps under duress in a few cases!) and an ex senior signal operator. They all bring strengths to the table, but the latter group stand out IMO.

As for train operators, yes the job is slightly deskilled in terms of route knowledge and the physical activity of driving the train - however this has never really been what the driver is paid for. They earn their money for keeping things going safely and smoothly come rain or shine, which in reality means being able to deal with problematic situations.
 

Dstock7080

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Test running on Saturday and Sunday, with an expectation passenger services may commence Sunday (as with the commissioning of Hammersmith) if all is going to plan.
Authorised for passenger use from 1230 today.
I’m sure you’ll give a full account soon!
 

ijmad

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Took a ride this evening. There was an odd gap in the eastbound service at Baker Street but I rather suspect this was due to the fire alert at Kings Cross rather than anything to do with the signalling. Also funny complaint from an H&C T/Op that "priority as always was being given to all other services before this one" as we were held at a 'red' signal (which of course aren't red any more, yay for anachronisms).

Is that a jibe at the computers letting Met services proceed before the Circle and H&C, or just a driver at the end of a long day?
grin.png


Anyway, it seemed to recover rather quickly when things got moving again, so actually a good sign. However, I did notice a couple of false starts where the white light illuminated, and the doors closed a few inches before slamming open again. Not sure what caused this, perhaps one of you insiders can shed light on it. The ride seemed very smooth, much smoother acceleration and precision stopping than when I took a ride on the SMA 0.5 section just after it opened, so I guess kudos for the new software versions smoothing things out! In particular, no problem with the precision stopping at Baker Street P5 where the train has to be very tight to get that last set of doors on coach six in to the platform.
 

bionic

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Is that a jibe at the computers letting Met services proceed before the Circle and H&

It's that age old driver mentality where everyone thinks priority is given to someone else. C&H drivers believe the Met and District get priority while if you ask a Met or District driver they will say the C&H always gets priority. You can apply this false 'logic' across the country... suburban drivers will be fed up waiting for expresses to go in front while the drivers of the expresses will complain about having to wait for the locals. Another part of this 'logic' is that the driver of the train that goes first is usually too slow... I imagine under ATO it will be their dwell times that are the problem!
 

simple simon

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It's that age old driver mentality where everyone thinks priority is given to someone else. C&H drivers believe the Met and District get priority while if you ask a Met or District driver they will say the C&H always gets priority. You can apply this false 'logic' across the country... suburban drivers will be fed up waiting for expresses to go in front while the drivers of the expresses will complain about having to wait for the locals. Another part of this 'logic' is that the driver of the train that goes first is usually too slow... I imagine under ATO it will be their dwell times that are the problem!

LOL, only train drivers think this way?

Nope. Passengers too!!

As a schoolboy I used to get very cross when on eastbound trains from Liverpool Street that were held to allow two or sometimes even three Districts to run non-stop in to Aldgate East, whilst we all stood there watching... powerless to do anything about it!

I still get very peeved with this, and with things like trains not seeming to travel as quickly as they used to when travelling from Stepney Green to Mile End. I have no evidence to prove this (other than watching the rate at which the tunnel wall passes by) but am convinced that the trains have been slowed down since the days of COP and R stocks.

Ditto with trains travelling from Farringdon to Kings Cross, compared with the 1970s when I used to get to ride in the A stock drivers cab on my way to school.
 

westv

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As a new signalling system has just been installed should it be unusual for signal failures at Aldgate now?
 

tomglazed

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The new signalling system was most recently fully rolled out up to Euston Square for H&C/Circle Lines and a portion of Met Line up to Euston Square also. It’s my understanding that the new system until fully rolled over, most sections act with the current legacy hardware (which is prone to failure due to age) and the new signalling is interfaced to it. Only once section by section is fully tested will the new system have full control over the section in question and legacy hardware be covered up or disabled.

Aldgate is still legacy hardware interfacing with the new system.
 

Dstock7080

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As a new signalling system has just been installed should it be unusual for signal failures at Aldgate now?
Aldgate is not due to transfer until 22/23 February.
This morning a point failure in the CBTC area suspended Metropolitan services for a while, so failures will still occur
 

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