Network Rail announces start of GWML resignalling

[whole diary]

[Oxman]

NR^» (Network Rail - home page) press release today:

http://www.networkrailmediacentre.co.uk/Press-Releases/RAIL-INVESTMENT-SIGNALS-START-OF-REVAMP-ON-GREAT-WESTERN-1a3a/SearchCategoryID-7.aspx

I particularly enjoyed the section on "How railway signalling works"! 

[Zoe]

Nothing about ETCS^▸ (European Train Control System) in that article.  I thought this was to be a key part of the resignalling.

[EBrown]

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

Great Western main line signalling scheme to begin


Network Rail said the upgrade was essential for the electrification of the line

A ^350m scheme to upgrade signalling on the Great Western main line is to begin later.

Network Rail said the improvements would benefit rail services through Bristol, Bath, Chippenham, Swindon, Didcot, Oxford and Newbury.

A spokesperson said the work was "essential" to prepare for expansion on the line and electrification.

The project has been paid for out of a Government settlement which had already been agreed.

Network Rail said the current system which controls the signals, known as interlocking, dates back to the 1960s.

A spokesperson said the project would effectively be a "brain transplant" with the old system being replaced by modern computers.

They said the four-year scheme, when finished, could "help cut delays on the line by 50%".

Patrick Hallgate, from Network Rail Western, said: "The line is running out of room with nearly 30m journeys and a growth rate of at least 5% each year.

"A robust and modernised signalling infrastructure is vital to cope with this burgeoning growth."

Last year the Government announced a ^5bn investment programme of rail electrification and intercity service improvements on the Great Western rail route.

[eightf48544]

Quote from the web link given by Oxman:

"These innovative signals have reliable LED powered lights, a lightweight structure requiring less foundation that can be lowered to the ground for safe, efficient maintenance."

Apparently what somebody forgot is that if you lower the post to the ground the signals become invisible to drivers. Therefore i,nstead of the technian working on the signal head in situ as they have done since the first signals, they now have to have a formal possessition to undertake the work!

I'm also not sure I like computer interlocking either: Points 8059B set from Line 3 to Up Main with SN109 at Red.

[Electric train]

Quote from the web link given by Oxman:

"These innovative signals have reliable LED powered lights, a lightweight structure requiring less foundation that can be lowered to the ground for safe, efficient maintenance."

Apparently what somebody forgot is that if you lower the post to the ground the signals become invisible to drivers. Therefore i,nstead of the technian working on the signal head in situ as they have done since the first signals, they now have to have a formal possessition to undertake the work!

I'm also not sure I like computer interlocking either: Points 8059B set from Line 3 to Up Main with SN109 at Red.

The operational life expectancy of LED lights is many 1000's of hours longer than tungsten filament lamps if fact LED's are measured in years, therefore lowering then to the ground to maintain them is not so much of an issue but staff working at hight is and the monstrous structures that are designed nowadays to support the weight of technicians to maintain signal heads.

As for computer interlocking its used all over the country, the failure at Ladbroke Grove was largely down to human error yes other "systems" failed to prevent the accident it could be argued that with no driver and the use of a fully automatic system the collision would not have occurred

[Zoe]

As for computer interlocking its used all over the country, the failure at Ladbroke Grove was largely down to human error yes other "systems" failed to prevent the accident it could be argued that with no driver and the use of a fully automatic system the collision would not have occurred

I think the above post was saying that had the points been set to for the Down Relief in the event of a SPAD^▸ (Signal Passed At Danger) then it could have reduced the scale of any collision.  The computer interlocking however did not do this.

[SandTEngineer]

As for computer interlocking its used all over the country, the failure at Ladbroke Grove was largely down to human error yes other "systems" failed to prevent the accident it could be argued that with no driver and the use of a fully automatic system the collision would not have occurred

I think the above post was saying that had the points been set to for the Down Relief in the event of a SPAD^▸ (Signal Passed At Danger) then it could have reduced the scale of any collision.  The computer interlocking however did not do this.

The interlocking concerned was not a computer but a Solid State Interlocking. Solid State Interlockings (or computers) don't think for themselves.  It did what it was programmed to do.  I'm sure at the time that the potential risks were analysed and that the decision was taken based upon the train being brought to a stand in the overlap clear of the Up Main rather than risk a side swipe on the Down Relief that could have potentially caused the train to tip into the Up Main and have three trains involved in a collision instead of two (pure speculation on my part).

Anyway the risks are now analysed in a much more quantified way and of course we have TPWS^▸ (Train Protection and Warning System) as well.

Back on topic.  The GWML^▸ (Great Western Main Line) resignalling is going to be interesting as I understand quite a few existing signal structures are going to be retained at the beginning until Crossrail comes along and renews them all!  .......and its a VERY ambitious delivery programme

[ellendune]

The interlocking concerned was not a computer but a Solid State Interlocking. Solid State Interlockings (or computers) don't think for themselves.  It did what it was programmed to do. 

Just as did does with interlocking using relays and old fashioned metal bars!

[JayMac]

I did like the 'brain transplant' comment from the NR^» (Network Rail - home page) spokesperson!

I just hope they don't get their new brain from Currys.

 

[TonyK]

Good-oh! But don't stop at Parson Street, carry on down, through Ashton Gate and Pill, to Portishead. Save having to come back later and splice it in. And while you're at it, put a bit of track down, will you?

[trainbuff]

Will the work at Parson Street include resignalling the junction there, for a Portishead reopening? After all a service to Portishead is included in the current GW^▸ (Great Western) Franchise proposals

[grahame]

Will the work at Parson Street include resignalling the junction there, for a Portishead reopening?

Don't know ... but there have certainly been a number of inputs with regard to quite minor (?) changes which could be incorporated now at a fraction of the time and trouble it would be to do them later.  I was noting elsewhere comments about calling on signals at Bristol Temple Meads, which might help capacity there.  And I would love to see a calling on signal for the Swindon bay to allow two trains to terminate there back to back.  With redoubling of Swindon to Kemble as well, seems the right time with the capital investment to say "what do we need to see us through 15 years"?

[Electric train]

seems the right time with the capital investment to say "what do we need to see us through 15 years"?

While foresightedness should be used when ever possible, 15 years is pushing it, if we look back 15 years ago the view was the railways were in terminal decline.  The real key is not to let the equipment, especially computer software, used on the railways get to the point it is not only obsolete but obsolescent which will make adding or altering things easier

[TonyK]

I agree with Electric Train about LED lights. Presumably, each aspect lamp will have  a fair number of LEDs, so a few blowing won't matter unduly. They are very robust. If this signalling project lasts as long as the one it replaces, many of the signals will pass their entire design lives without having the lights changed.

[eightf48544]

seems the right time with the capital investment to say "what do we need to see us through 15 years"?

While foresightedness should be used when ever possible, 15 years is pushing it, if we look back 15 years ago the view was the railways were in terminal decline.  The real key is not to let the equipment, especially computer software, used on the railways get to the point it is not only obsolete but obsolescent which will make adding or altering things easier

Grahame's comment goes to the heart of the problem, the need for foresight, whilst Electric train's comment highlights a real problem with modern computer controlled signalling. Version control.

As I understand it the idea is that each component e.g a signal, point etc is modular and can be just plugged into the system. The problem will be ensuring that as the  software evolves that it is backward compatible, because otherwise it will be a real nightmare upgrading the software on all lines and trains (don't forget with ECTS there is an integral train component to the signalling as well) at the same time. 

You only have to look at the problems people get moving to different versions of Windows. Multiply that to updating every signalling processor component and train and you get picture.

In railway terms Networkrail must learn from the Belgium/Dutch LGV^▸ (Large Goods Vehicle) where there were major problems integrating the two different ECTS software versions making sure the trains could understand the diferent mesages being transmitted to them by the two systems. I'm not sure if they've got it working at full capacity/speed even now.