Kings Cross tunnel

[FrozenPoints]

I'm wondering if there is a case to open the third tunnel at Kings Cross. It seems like it is in good condition.

Is there a case for it. What would it cost amongst many pondering questions.

 

[LE Greys]

I'm wondering if there is a case to open the third tunnel at Kings Cross. It seems like it is in good condition.

Is there a case for it. What would it cost amongst many pondering questions.

Well, the old arrangements were a bit complicated. You could open the east bore at Gasworks Tunnels, but that would mean six lines filtering down to four at Belle Isle. Opening up the east bore of Copenhagen Tunnel would be more complicated, because the flyover does not give enough width to fit two more lines underneath (one perhaps, but not two). It might be possible to move one line to the east side of the flyover (which would mean demolishing the remains of the old flyover to do so) to connect the up goods to the east bore of Copenhagen, presumably for ECS workings. Both east bores are a couple of feet lower than the centre bore, so clearance for the OHL might be a problem.

However, if many suburban services are diverted into Thameslink at Belle Isle, then this will not be such a great concern. This would reduce suburban traffic, but would lead to up Thameslinks crossing the down slow. There is no real way to compensate for that, a second flyover at Belle Isle is unlikely - there is not enough room. A diveunder might work, but only if it could clear the Piccadilly Line which runs underneath. Reopening the York Road Curve might be possible, but is also unlikely because of Platform 0 (not enough room for OHL either). The opposing Hotel Curve is now full of sewers, and there is not enough room to reinstate Platform 14. Another good thing is that 9, 10 and 11 might be useful for HT and GC (it's long enough for a single Della or a 2+5 HST) when the suburban trains move out.

 

[swt_passenger]

The need for three tunnels lapsed with the resignalling and remodelling that reduced the layout to something very like the current set up during the later 1970s, around the time of the GN suburban electrification.

I'm fairly sure that this also coincided with changed operating practices giving a massive reduction in light engine and coaching stock movements, the closure of the links to the widened lines (that's the Hotel and York Rd curves which gave access to Moorgate via Farringdon transferred to the Midland route), and the eventual diversion of some inner suburban trains down to Moorgate from Finsbury Park.

Last but not least, there were a number of goods yards in the area that closed - so I'd assume they simply worked out that a four track approach to KX was perfectly adequate.

Another point is that all 4 modern lines are fully bidirectional, so they probably have as much flexibility as the previous 6 lines anyway...

PS - I've never seen a modern proposal to reinstate the third tunnel, in any of the various NR plans or RUSs -which suggests no-one reckons it is needed.

 

[FrozenPoints]

*Apologies for the 3 set of threads for this....I thought I posted a standalone one, but seemingly it ended up in THREE including the 'doors' one.

I thought it would create some operational flexiblity and I would be in favour of maintaining the tunnel to a condition when the time comes to look at re-opening the tunnel at the very least.

It just looks so appealing, ready to be reused. But whether you could compare it to the likes of Paddington and Euston which have more tracks around their throat areas.

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9, 10, 11 - I had no idea FCC were moving out. When are they doing so? Is this in design for the new Thameslink where you can travel from Brighton - Cambridge etc. Are they keeping Moorgate?

 

[swt_passenger]

I thought it would create some operational flexiblity and I would be in favour of maintaining the tunnel to a condition when the time comes to look at re-opening the tunnel at the very least.

It just looks so appealing, ready to be reused. But whether you could compare it to the likes of Paddington and Euston which have more tracks around their throat areas.

I've found an old copy of Modern Railways from 1977 that explains it all. The key thing is that the 6 lines for 15 passenger platforms didn't go very far - basically the station throat was extended through Gasworks Tunnels only. Because they were arranged as three up and three down there were a number of massive conflicts when up trains were arriving and down trains were leaving. EG a train departing from platform 1 prevented any simultaneous arrivals. Also, the outermost lines, the down slow and up slow had very limited access to the station. The route from the up slow ran through the York Rd platform and into P1 of the main shed only. The down slow was similarly of limited use for services from the main shed, its main role was to deal with trains from Moorgate. So once the decision had been made to transfer the Moorgate via Farringdon service to the Midland those two lines were of very limited use.

However between Copenhagen and Gasworks tunnels there were only actually four passenger lines aligned with the eastern and central bores of the former, because the pair of tracks through Copenhagen West tunnel was for freight only, and diverged to the goods depot. There was a single track connecting link between that freight pair and the down slow. So it's arguable that there never really was a 6 track approach.

The simplified track layout required for the new four track bidirectional approach then allowed for the remaining platforms to be extended and straightened. Pairing by use (the current layout) is acknowledged to be a much more efficient approach to a terminus than pairing by direction ( the old layout). So all said, the rebuild didn't lose any operational flexibility, it improved it a great deal.

I don't think there's any need to worry about the tunnel being maintained in good condition though, as they are obliged to consider the safety of everything above it, such as the canal...

9, 10, 11 - I had no idea FCC were moving out. When are they doing so? Is this in design for the new Thameslink where you can travel from Brighton - Cambridge etc. Are they keeping Moorgate?

They aren't completely moving out. Alhough a significant proportion of the offpeak suburban service will go to Thameslink, there will still be some remaining services all day, and there will be a number of peak extra FCC services into Kings Cross.

Moorgate will have an enhanced service via Finsbury Park in any case.

 

[Aictos]

They aren't completely moving out. Alhough a significant proportion of the offpeak suburban service will go to Thameslink, there will still be some remaining services all day, and there will be a number of peak extra FCC services into Kings Cross.

Moorgate will have an enhanced service via Finsbury Park in any case.

Indeed with more Hertford Loop services as a result being touted by Network Rail.

 

[Lee_Again]

Indeed with more Hertford Loop services as a result being touted by Network Rail.

I'd like to see 4tph on the Hertford Loop too. 2 stoppers and 2 semifast continuing to Letchworth. However, and this is a big leap... 1 stopper and 1 semifast to go to, instead of Moorgate, but on to the North London Line and down to South East London. i.e. an extension of the new Overground services.

Further, put the 2 Cambridge fasts on the loop, passing the slows at the reinstated loops at Gordon Hill. This would free up 2 paths across the Welwyn viaduct.

Going back to the Kings Cross tunnels. No need for 6 through the first but I'd put six in the second. I would then have a grade seperated junction keeping the new Thameslink services seperate from the other lines until at least Alexandra Palace. This would have the effect of grade seperating the whole service from the East Coast services.

With a bit of extra investment the semi fasts (Finsbury Pk > Stevenage) could also go on the loop; again, passing the slows at Gordon Hill. This would mean that only 2 slows go across the viaduct, giving at least 10 paths for East Coast (and the open access guys).

This is part one of my 'dream'; sorry to ramble.

 

[Nym]

Going back to the Kings Cross tunnels. No need for 6 through the first but I'd put six in the second. I would then have a grade seperated junction keeping the new Thameslink services seperate from the other lines until at least Alexandra Palace. This would have the effect of grade seperating the whole service from the East Coast services.

With a bit of extra investment the semi fasts (Finsbury Pk > Stevenage) could also go on the loop; again, passing the slows at Gordon Hill. This would mean that only 2 slows go across the viaduct, giving at least 10 paths for East Coast (and the open access guys).

This is part one of my 'dream'; sorry to ramble.

The first part makes very good sense, Having 6 tracks all the way to Finsbury Park for Thameslink would be a very good plan.

Renew the 3rd bridge over Halloway Road, dedicated Thameslink tracks all the way to Finsbury Park.

 

[LE Greys]

The first part makes very good sense, Having 6 tracks all the way to Finsbury Park for Thameslink would be a very good plan.

Renew the 3rd bridge over Halloway Road, dedicated Thameslink tracks all the way to Finsbury Park.

The awkward bit there would be the new flyover (current up slow). The old one carried the up goods that swt_passenger mentioned up the thread, connecting from the easternmost arch of Holloway Bridge to the western bore of Copenhagen Tunnel. The new flyover is at a less acute angle, allowing passenger trains to cross it at a higher speed, but that means it links into the up slow, two arches west of the old one. There might just be enough room to squeeze in one line between it and the up fast, but not two. The other one would have to go around the outside, probably linking from the up goods. This would mean it would only be any use for ECS, otherwise all the other problems swt mentioned would recur.

There is an alternative. Making both bores of Copenhagen bi-di and adding two extra crossovers at Belle Isle - down slow/up slow and up slow/down fast - would give an alternative route for trains coming in from Finsbury Park, reducing pressure on the flyover and improving access from the fast lines to the suburban platforms. It would probably cost less as well, but would take a bit of resignalling to do.

Belle Isle Currently:
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GWT<>____/______________>CT
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My idea:
----<>________________\__<>>----
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GWT<>____/___\__________<>>CT
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[Nym]

Proberbly a silly question, is the junction just north of St Pancras Thameslink going to be grade seperated or will the ECML services need to cross the lines on the flat?

 

[LE Greys]

Proberbly a silly question, is the junction just north of St Pancras Thameslink going to be grade seperated or will the ECML services need to cross the lines on the flat?

Judging by the alignment of the new portal, it's going to be flat. Seems a bit daft, but there is nowhere to put in a portal in between the lines at Belle Isle. The only other option would be a long, twisting tunnel leading into Copenhagen East Bore, and that's very complicated to do.

 

[Lee_Again]

Proberbly a silly question, is the junction just north of St Pancras Thameslink going to be grade seperated or will the ECML services need to cross the lines on the flat?

Fairly certain it is grade seperated. The down line dives under the existing formation.

What would have made a real difference is for SPTL to be two island platforms. I would have also made this the changeover point to 3rd rail. Having a passing loop in that section would solve a whole myriad of problems.

While the signalling system can cope with 24tph I really doubt the ability of passengers to do the same. SPTL is always busy in the evenings and the platforms can get very crowded.

 

[Nym]

Would have made good sense yeah, having two island platforms, with either side for the ECML and MML routes, would mean not waiting outside StP for a platform either, would be going straight in. Tracked and signalled as all accessable but by convention using certain platforms.

Time will tell on what happens, one does wonder if there would be space to add this later, but I'm dowbting it, without some cerious tunneling, full bore either side of the current box.

 

[LE Greys]

Would have made good sense yeah, having two island platforms, with either side for the ECML and MML routes, would mean not waiting outside StP for a platform either, would be going straight in. Tracked and signalled as all accessable but by convention using certain platforms.

Time will tell on what happens, one does wonder if there would be space to add this later, but I'm dowbting it, without some cerious tunneling, full bore either side of the current box.

Also useful if they had enough crossovers at both ends to terminate trains at St P during engineering work. Changing to 3rd rail there would be a good idea, to save space in the tunnels as much as anything else, also to make it easier to isolate the tunnel electrification for maintenance, terminating trains from north or south as need be.

 

[mr_jrt]

I always though it'd make a lot of sense to move as much of the pointwork as possible north of the canal tunnels, and just have mostly plain line to the platforms, permitting further extensions to the platforms (16-car trains?). Perhaps even opening up the tunnels a bit (sticking the road onto a bridge and and canal onto an aquaduct), and getting even more space to work with.

Something like:
Eastern bore: Access to platforms 0, 1, 2, 3, 4
Central bore: Access to platforms 3, 4, 5, 6
Western bore: Access to platforms 7, 8, 9, 10, 11

The alignment from the central bore to platform 0 has a strong curve to it. Had they moved a large chunk of the eastern pointwork north of the canal tunnels and used the eastern bore they could have easily lengthened platforms 1, 2 and 3 as well.

Or something like that.

 

[ole man]

Just outside Kings Cross there are tunnels, Gaswork Tunnels i think, one of the tunnel portals has a shunt road, and the other looks as if you can drive down it, has it always been like this?

 

[swt_passenger]

Just outside Kings Cross there are tunnels, Gaswork Tunnels i think, one of the tunnel portals has a shunt road, and the other looks as if you can drive down it, has it always been like this?

No, prior to the GN suburban electrification in the 1970s it was completely different.

There was a pair of lines in all three tunnels, reading across from east to west the tracks through the three Gasworks tunnels were up slow & up fast, up relief & down fast 1, down fast 2 & down slow.

Then between the north end of the Gasworks tunnels and the south end of the Copenhagen tunnels the track layout altered to allow for the goods depot junction. Now reading east to west it was up slow & up fast, down fast & down slow, up freight & down freight. The up side changed from two to three tracks between the tunnels, in the opposite direction the three down tracks became two, but there was a link between the down slow and the up & down freight lines.

The Holloway flyover north of the Copenhagen tunnels was originally there to get the up freight traffic over the four passenger lines - nowadays it has been reworked to get the up slow over the fast lines - ie changing from the paired by direction layout south of and through Finsbury Park to the paired by use layout approaching the station.

Drawing attached, only shows Gasworks tunnel but you should get the idea:

 

[ole man]

Your maps of London and everything disused are top notch.
Why did they close the tunnel portals?

 

[swt_passenger]

Don't know - I suspect with the reduction in freight traffic, and full bi-di working with the new layout they just weren't thought to be needed.

I've wondered though why they couldn't at least use the eastern bores as stabling, just to shunt trains clear of the main shed platforms in busy periods.

One plan I did read about somewhere was to utilise the now spare Copenhagen tunnel to run an airport express service from a new dedicated station on the goods yard site, via a new S>E junction onto the Tottenham and Hampstead (ie the GOBlin), this was back in the days when London's third airport was going to be at Maplin Sands. That definitely dates that idea a bit...

 

[Bald Rick]

Back in the day, everything that came up the ECML went to KX, either main station, via the York way platform to the widened lines, or into KX goods yard. The exception was the occasional service to Broad St via the Canonbury curve and NLL.

With the construction of the link from Finsbury Park to the Northern City line at Drayton Park, most of the inner suburban service was diverted to Moorgate. So no need for 6 tracks right to the platforms at KX. And frankly with current and future traffic levels there still isn't.

Also the old throat at KX was pretty horrible, with an 8mph speed limit I think. Simplifying the layout to four approach lines helped to raise the line speed to a whopping 15mph as it is today.

 

[LE Greys]

Back in the day, everything that came up the ECML went to KX, either main station, via the York way platform to the widened lines, or into KX goods yard. The exception was the occasional service to Broad St via the Canonbury curve and NLL.

With the construction of the link from Finsbury Park to the Northern City line at Drayton Park, most of the inner suburban service was diverted to Moorgate. So no need for 6 tracks right to the platforms at KX. And frankly with current and future traffic levels there still isn't.

Also the old throat at KX was pretty horrible, with an 8mph speed limit I think. Simplifying the layout to four approach lines helped to raise the line speed to a whopping 15mph as it is today.

It also gave an opportunity to put suburban traffic on the flyover at Holloway. Before this, that was goods only and very slow, so anything going into the suburban side had to cross both fast lines, although as you say, a lot of traffic went down into the Widened Lines. This allowed the suburban service to get up to current levels (I think it was 2tph beforehand, now it's 4tph plus extras). The biggest annoyance is that they closed Platforms 11-15, although they eventually restored 11 and added 0, meaning that Platfom 8 now often ends up with suburban stock in it, although usefully it's long enough for a 12-car formation.

The bottleneck is not really Gas Works Tunnel though, it's Welwyn. Anyway, Thameslink should absorb a lot of the suburban traffic, so perhaps we might see Hull Trains and Grand Central operating out of 9, 10 and 11.

 

[OuterDistant]

Cah, 6 posts in and yet no one's mentioned Mrs. Wilberforce!

 

[LE Greys]

Cah, 6 posts in and yet no one's mentioned Mrs. Wilberforce!

Didn't she live over Copenhagen Tunnel? Although she did have a secret passage to Euston Road it seems.

 

[34D]

Very informative thread everyone

so perhaps we might see Hull Trains and Grand Central operating out of 9, 10 and 11.

They'd need a platform each though, whereas the trainshed platforms can (and have) had a GC HST atop an adelante.

I have however seen both HT and GC in the sub.

 

[ole man]

Who is Mrs Wilberforce?

 

[qpsnapper]

Who is Mrs Wilberforce?

She's from The Ladykillers - classic film and (for a few more weeks anyway) a very good play in the West End.