Thameslink Easter works

[Edvid]

This Easter weekend, I believe the plan was to commission the bi-di signalling between City Thameslink and Loughborough Junction, as well as the bay platform/approach tracks at Blackfriars. Is this happening as planned?

Would also like to know if the NR/LU ticket offices at Farringdon are going to open right after this weekend.

 

[Bald Rick]

The resignalling is high capacity plus bi-di City Thameslink to Union Street Jn, then straight uni-directional resignalling to a higher capacity from there to the 2 3/4milepost. The bay platforms at Blackfriars are also being commissioned, albeit they won't be used until the TT change in May. Finally the proceed on sight aspects (POSAs) are being brought into use through the core section. The work is on schedule.

Can't answer question 2.

 

[causton]

What is the purpose of the POSAs? I mean, I know what they do, but what improvements do they have over the traditional signalling?

 

[Bald Rick]

When there's a straight signal or track circuit failure, the POSA can be set and the driver doesn't need cautioning past the red. Had POSAs been available for the last 5 months, about 70% of the significant delays experienced on the TL core section would have been completely avoided.

 

[causton]

I see, that makes sense seems a good idea, although hopefully NR will make the existing signalling less prone to failure so the POSA signals would need to be used less and less... Obviously, everything comes through to the public as a 'signal failure' so I don't know what causes most of the frequent Thameslink delays so I can't comment much more on if/how they can be easily solved!

 

[A60K]

Interesting, thanks. What happens with AWS/TPWS on POS working - are they disabled or will the train trip at a red signal like on LU?

 

[Skoodle]

TPWS is not active when a POSA is flashing, just like a normal position light.

 

[Class377/5]

The last final big Core engineering work left. After this, the TLP is all about London Bridge.

 

[swt_passenger]

POSAs are covered in a dedicated rule book module if anyone is interested:

http://www.rgsonline.co.uk/Rule_Boo...ight Authority (PoSA)/GERT8000-PoSA Iss 1.pdf

Apparently they are already in use on the ELL core section (ie the TfL infrastructure).

 

[Bald Rick]

Indeed they are, but have been used very rarely, principally because the axle counters are pretty reliable. Unlike the track circuits in Thameslink, which have all sorts of stray currents to deal with.

 

[swt_passenger]

Indeed they are, but have been used very rarely, principally because the axle counters are pretty reliable. Unlike the track circuits in Thameslink, which have all sorts of stray currents to deal with.

Yes - I suppose by 'in use' I really meant 'available for use'. In principle, as a fall back mode for use when particular defects occur, they should hardly ever see actual use.

Any idea why Thameslink has stuck with track circuits rather than axle counters though?

 

[Bald Rick]

The first question I asked when I got involved last year. Apparently it's because the core section has so many train detection sections, through a combination of very short signal sections, bi-di, and a fair bit of pointwork. Having axle counters would have added considerably to the amount of cabling and trackside equipment in the tunnels, and also to interlocking complexity. Not sure I buy that but then I'm no signal engineer.

 

[asylumxl]

The first question I asked when I got involved last year. Apparently it's because the core section has so many train detection sections, through a combination of very short signal sections, bi-di, and a fair bit of pointwork. Having axle counters would have added considerably to the amount of cabling and trackside equipment in the tunnels, and also to interlocking complexity. Not sure I buy that but then I'm no signal engineer.

My bet is on the money.

 

[Bald Rick]

My bet is on the money.

Definitely not that!

 

[Class377/5]

The first question I asked when I got involved last year. Apparently it's because the core section has so many train detection sections, through a combination of very short signal sections, bi-di, and a fair bit of pointwork. Having axle counters would have added considerably to the amount of cabling and trackside equipment in the tunnels, and also to interlocking complexity. Not sure I buy that but then I'm no signal engineer.

I'm not a signal engineer (should ask one as I see them daily) but could it be with the ATO planned? Due to the nature of the Core signalling, the new 12 cars will foul the two signals behind the one it stands at, so they used track circuits to position the train correctly?

On a positive note, the first train had arrived on platform 4 at Blackfriars before I left work, so seems all's well. ( If not, I'm gonna have a bad day tomorrow).

 

[Edvid]

Am I right in presuming the bays can accommodate 12-car services?

 

[Class377/5]

Am I right in presuming the bays can accommodate 12-car services?

Yes. However in its current set up you cant access the bays and London Bridge directly.

 

[Wolfie]

There was major activity at London Bridge over the Bank Holiday weekend - caused traffic chaos due to diversions - seemed to be bridge related....

A question - is the new structure and gate line on the London Bridge terminal lines permanent? Much lighter and brighter but doesn't seem very substantial and it is grafted onto the extant concourse/ticket hall which I believe is going.

A question/comment: I saw a named FCC class 319 at London bridge - named after a driver - think it was Arnold something or other.....anyone have any info - a nice gesture which would have been better if the nameplate had not been merely vinyl and had it actually been put on properly ie horizontally as opposed to at an angle.......typical FCC!

 

[thelem]

That'll be 319 435

"Adrian Jackson-Robbins
Chairman 1987-2007
Association of Public Transport Users"

Full list at http://www.thejunction.org.uk/flist_319.html

 

[jon0844]

Damn, I was hoping it was going to be Arnold J Rimmer.

 

[swt_passenger]

Am I right in presuming the bays can accommodate 12-car services?

I'm a bit surprised this question often gets asked.

I have copies of drawings from the TWA Act going back as long ago as 2003 which show the bays as 12 car length.

Mind there was a period just a few years ago when someone who apparently worked at Blackfriars was denying that the platforms would be 12 car...

 

[Class377/5]

I'm a bit surprised this question often gets asked.

I have copies of drawings from the TWA Act going back as long ago as 2003 which show the bays as 12 car length.

Mind there was a period just a few years ago when someone who apparently worked at Blackfriars was denying that the platforms would be 12 car...

Thing the confusion was only the 12 car through platforms were ever really spoken about being 12 car length where as the bays aren't as long as the through platforms. There is a fair length of the through platforms that aren't for boarding but sectioned off from the track at the north end.

There was major activity at London Bridge over the Bank Holiday weekend - caused traffic chaos due to diversions - seemed to be bridge related....

A question - is the new structure and gate line on the London Bridge terminal lines permanent? Much lighter and brighter but doesn't seem very substantial and it is grafted onto the extant concourse/ticket hall which I believe is going.

A question/comment: I saw a named FCC class 319 at London bridge - named after a driver - think it was Arnold something or other.....anyone have any info - a nice gesture which would have been better if the nameplate had not been merely vinyl and had it actually been put on properly ie horizontally as opposed to at an angle.......typical FCC!

There is a 319 named after a driver as well. Can't remember for the life of me but I'm sure it's Mick something. It's Vinyl as long term the units are unlikely to keep any FCC nameplates. However a name plate was made and given to the widow of said driver.

 

[swt_passenger]

There is a fair length of the through platforms that aren't for boarding but sectioned off from the track at the north end.

That very point is explained on the 2003 drawing I'm referring to though. By using the drawing's scale it is possible to dimension the four platforms, and it clearly shows that the buffer stop positions in the new bays are further north than the working length limit of the through platforms, ie past the 'unused section' of the through platforms, that are now obvious in the as built state.

 

[Class377/5]

That very point is explained on the 2003 drawing I'm referring to though. By using the drawing's scale it is possible to dimension the four platforms, and it clearly shows that the buffer stop positions in the new bays are further north than the working length limit of the through platforms, ie past the 'unused section' of the through platforms, that are now obvious in the as built state.

Ah some of the station plans weren't proper technical drawings so scaling didn't work.

 

[Wolfie]

There is a 319 named after a driver as well. Can't remember for the life of me but I'm sure it's Mick something. It's Vinyl as long term the units are unlikely to keep any FCC nameplates. However a name plate was made and given to the widow of said driver.

Hum interesting - and the real name plate was a nice touch - I presume the driver dies in service?

Given the confusion I think I may just ask FCC.