Signalling - centralised operations may lead to wider problems in the future?

[whole diary]

[thetrout]

2M11 on Melksham single line changing ends and diverted via Bristol upon arriving and reversing at Bradford Junction (0704 Westbury-Gloucester)

Did that service actually reverse at Bradford Junction? I wouldn't have thought that would be possible as most moves such as this would be done at Westbury where the platforms are bidirectional.

Of course am happy to be corrected... Just didn't think that was possible and even allowed...?

For the second time today, another prime example of the Melksham - Bradford-on-Avon part of the Bradford Junction Triangle...

[rogerw]

Quite possible to reversse at Bradford Junction.  It is a fully signalled move.

[Louis94]

1A04 was allowed to continue once override switches has been switched in between Swindon and Didcot

I may know a little more about signalling than your average man in the street but I'm a bit mystified by these overrides of which you speak - can you elaborate? Are you talking about manually keying the automatic signals back to danger and allowing trains to pass using handsignallers, or of a method of operation that I've apparently never heard of?

If I am entirely honest I am not 100% sure myself! All I know is that these switches control a far bigger area than a just one signal. All I can imagine is that they allow on the ground staff to control a trains without the signal box - if anyone does know there function I would be very interested!

[swrural]

Quite possible to reversse at Bradford Junction.  It is a fully signalled move.

Ah, that was what I was asking the other day (the mythical main line 'Lacock' bridge incident with the river flowing under it     remember) and I was given the impression one had to take the HST^▸ (High Speed Train) to Westbury.

So the triangle completed woould be dead handy as a permanent feature (not just for electrification, although needing thunderbird engines at Chippenham and Bathampton, I suppose) but it could be managed already, interesting.

[SandTEngineer]

1A04 was allowed to continue once override switches has been switched in between Swindon and Didcot

I may know a little more about signalling than your average man in the street but I'm a bit mystified by these overrides of which you speak - can you elaborate? Are you talking about manually keying the automatic signals back to danger and allowing trains to pass using handsignallers, or of a method of operation that I've apparently never heard of?

If I am entirely honest I am not 100% sure myself! All I know is that these switches control a far bigger area than a just one signal. All I can imagine is that they allow on the ground staff to control a trains without the signal box - if anyone does know there function I would be very interested!

The local overides (quite a new facility on the Western) as opposed to remote overides worked from the relevant signalbox panel, put the signalling into what is called 'Through Routes' mode.  All of the principal running lines controlled interlocking signals are set up for the main running movements and they then work automatically without signaller intervention.  All remote interlockings at panel signalboxes have some form of 'Overide' that will set and put 'Through Routes' into operation.  Some panels also have 'Selective' overide.  This can be used to select key routes at critical junctions. Although all of these remote panel overides are usually sufficient and are battery backed up, these are no good if the signalbox panel gets blacked out (which is an extremely rare event).

[ellendune]

The local overides (quite a new facility on the Western) as opposed to remote overides worked from the relevant signalbox panel, put the signalling into what is called 'Through Routes' mode.  All of the principal running lines controlled interlocking signals are set up for the main running movements and they then work automatically without signaller intervention.  All remote interlockings at panel signalboxes have some form of 'Overide' that will set and put 'Through Routes' into operation.  Some panels also have 'Selective' overide.  This can be used to select key routes at critical junctions. Although all of these remote panel overides are usually sufficient and are battery backed up, these are no good if the signalbox panel gets blacked out.

So do these local overides basically allow some box by the side of the line somewhere to work automatically?

And I suppose that means someone actually going there to press the button?

If the panle had not blacked out could the panel have done this remotely?

[SandTEngineer]

The local overides (quite a new facility on the Western) as opposed to remote overides worked from the relevant signalbox panel, put the signalling into what is called 'Through Routes' mode.  All of the principal running lines controlled interlocking signals are set up for the main running movements and they then work automatically without signaller intervention.  All remote interlockings at panel signalboxes have some form of 'Overide' that will set and put 'Through Routes' into operation.  Some panels also have 'Selective' overide.  This can be used to select key routes at critical junctions. Although all of these remote panel overides are usually sufficient and are battery backed up, these are no good if the signalbox panel gets blacked out.

So do these local overides basically allow some box by the side of the line somewhere to work automatically?

And I suppose that means someone actually going there to press the button?

If the panel had not blacked out could the panel have done this remotely?

The switches are located where only authorised railway staff can access them (I'm obviously not going to tell you where).

Somebody has to go to the site (that is why they are called 'Local Overide Switches'  )

If the panel had not been blacked out but the remote control had been lost then the signaller could have introduced it.

[Chris from Nailsea]

From the BBC^» (British Broadcasting Corporation - home page):

West Sussex fire alert leads to train passenger delays

Rail passengers have been facing delays after a fire alarm led to the evacuation of a railway signal centre. Emergency services cleared Three Bridges station in Crawley, West Sussex, after fire alarms were sounded on Friday morning.

Southern services between Brighton and Horsham via East Croydon and First Capital Connect trains between Brighton and East Croydon are disrupted. First Great Western trains between Gatwick and Redhill are also delayed. The train firms have warned passengers to expect delays and some cancellations until about 16:00 BST.

In a statement, Southern said: "Train services across the Southern network are currently disrupted due to an earlier fire alarm activation in the Three Bridges signalling centre, resulting in the main signalling centre being evacuated. Delays of up to 45 minutes can be expected. Services will remain subject to short notice alteration, delay or cancellations this afternoon."

RMT^▸ (National Union of Rail, Maritime & Transport Workers) General Secretary Bob Crow praised staff for the "exemplary fashion" in which they carried out the emergency procedures but said he thought plans to centralise signalling operations could lead to worse disruption in future. He added: "RMT now awaits an inquiry into the full facts behind the incident and the evacuation and the union expects to play a full role in the investigation and the drawing up of any conclusions and recommendations. However, RMT believes that this morning's incident shines the spotlight on plans to centralise signalling operations into 14 regional centres, a move that clearly throws up real risks of putting all the eggs in one basket with the obvious problem of a whole region going down if a centre is taken out of action."

A spokesman for Network Rail said: "The investment we're making to upgrade Britain's railway signalling systems will mean that incidents like this morning's fire alarm at our Three Bridges control room will have significantly less impact on the travelling public in future. Currently, a number of different signalling systems are used across Britain's railway, meaning that if a problem occurs at a control room our options are extremely limited. Our new rail operating centres will all use a single system, meaning control of a section of railway can quickly and easily be transferred to another centre if needed."

[SandTEngineer]

From the BBC^» (British Broadcasting Corporation - home page):

A spokesman for Network Rail said: "The investment we're making to upgrade Britain's railway signalling systems will mean that incidents like this morning's fire alarm at our Three Bridges control room will have significantly less impact on the travelling public in future. Currently, a number of different signalling systems are used across Britain's railway, meaning that if a problem occurs at a control room our options are extremely limited. Our new rail operating centres will all use a single system, meaning control of a section of railway can quickly and easily be transferred to another centre if needed."

...so NR^» (Network Rail - home page) are going to train all of its staff at the Railway Operation Centres to work a bit of the railway anywhere in the UK^▸ (United Kingdom) at the drop of a hat.....  Pigs might learn to fly sooner

[paul7575]

I suggest what they'll have to do is organise the ROC^▸ (Rail Operating Centre - a centralised location for railway signalling and train control operations for a specific route or region)'s building, both its structure and its mechanical and electrical systems, so that the first reaction to a smoke alarm is NOT to immediately evacuate the whole building until such time as it's found to be a false alarm.  There may be fairly straightforward ways to subdivide or compartmentalise the ROCs into operating, ancillary and domestic areas. 

The operating floor (or whatever idea they come up with) doesn't actually have to be one massive room for the whole NR^» (Network Rail - home page) route/region, does it?

Paul

[SandTEngineer]

The operating floor (or whatever idea they come up with) doesn't actually have to be one massive room for the whole NR^» (Network Rail - home page) route/region, does it?

Paul

...but they are going to be...

[bobm]

Of course it doesn't have to be a fire.  Think of the problems over a wide area when there was a power failure at Swindon Panel in February. http://www.firstgreatwestern.info/coffeeshop/index.php?topic=12086.0

Are there any plans to have local emergency control in case of problems?  As I understand it there used to be (maybe still are) emergency mini-panels at places like Weston-super-Mare and Newbury which could operate in cases of a failure at the main centre.

Hopefully such disruption is rare and is that the thing which sways the argument in favour of the cost savings of centralisation?  The electricity grid is controlled from one central point in Berkshire but does have a back-up centre in the Midlands.  The lights going out over a wide part of the country due to a failure is likely to be more serious than trains being on stop in the great scheme of things.

[devon_metro]

I understand it will be possible for control to be temporarily transferred to another one of the large signalling centres on spare panels set aside in the event of failure.

[Chris from Nailsea]

Of course it doesn't have to be a fire.  Think of the problems over a wide area when there was a power failure at Swindon Panel in February. http://www.firstgreatwestern.info/coffeeshop/index.php?topic=12086.0

Thanks for that reminder, bobm - I've therefore taken this opportunity to merge both topics here, in the interests of continuity and completeness ... 

[Electric train]

Of course it doesn't have to be a fire.  Think of the problems over a wide area when there was a power failure at Swindon Panel in February. http://www.firstgreatwestern.info/coffeeshop/index.php?topic=12086.0

Thanks for that reminder, bobm - I've therefore taken this opportunity to merge both topics here, in the interests of continuity and completeness ... 

There is a lot of work being done to improve along track signalling power supply systems, auto reconfigurable systems are going to be the norm the demo's I've seen they can switch out a fault within milliseconds although a delay of several seconds has to be built in to allow signalling system to let the signals go black before restoring the power.  Within ROCs^▸ (Rail Operating Centre - a centralised location for railway signalling and train control operations for a specific route or region) and the outlying remote locations again a lot of design work has been done to make the power system as secure as possible