HS1 "covered way" viaduct

[kentuckytony]

[If this is answered somewhere else, please advise.]

Several of us in the USA were wondering about something we have seen.

As the HS1 line comes out of its tunnel before St. Pancras International, it goes over a viaduct that is still inside a "tube" structure.
Quail/TrackMaps refer to this section as a "covered way".

Why is this section under cover even though it is on a viaduct?

[I know there is something similar on the LO at Shorditch but this is for future buidling over the top of it without service disruption.]

 

[asylumxl]

I'm unsure, and despite using HS1 many times, my recollection of the exact part you mentioned is poor But I'd imagine it's to do with the conditions it was granted planning permission on. Probably to reduce noise pollution and hide it away, but this is a total guess.

 

[TGV]

I wondered the same thing while looking at it one day. I know where to find the answer so I'll report back when I find out, but my initial thoughts were that it was either to prevent anything landing on the line from the slope to the east of the ECML or something to do with isolating interference between HS1 and ECML - but these are all guesses. Watch this space.

 

[YesToHS2]

Isn't that the section they refer to as the "portal"? Probably just for aesthetics and as asylumxl said, noise mitigation.

 

[Striker]

I'm unsure, and despite using HS1 many times, my recollection of the exact part you mentioned is poor But I'd imagine it's to do with the conditions it was granted planning permission on. Probably to reduce noise pollution and hide it away, but this is a total guess.

He's talking about this, over the ECML north of Kings Cross.

 

[asylumxl]

I'd imagine the sooner and thus slower the train enters an enclosed space, the gentler the changes in pressure would be. But I doubt this is what it's for. I'm going to go with reducing noise, but also think TGVs comment about interference could be true, as the OHLE could interfere with beacons for TVM.

 

[swt_passenger]

Definitely a noise reduction barrier, as explained on the HS1 website.

"The bridge resembles a giant tube due to the acoustic grey cladding that will shield the local environment from CTRL train noise. The bridge will take Eurostar and CTRL domestic services from St Pancras station over the ECML and into the west portal of the CTRL London tunnel."

http://www.highspeed1.com/news/?page=7&id=127

Unlikely the ECML OHLE could be a problem, as it's relatively speaking no nearer than the HS1 OHLE?

 

[TGV]

Definitely a noise reduction barrier, as explained on the HS1 website.

"The bridge resembles a giant tube due to the acoustic grey cladding that will shield the local environment from CTRL train noise. The bridge will take Eurostar and CTRL domestic services from St Pancras station over the ECML and into the west portal of the CTRL London tunnel."

http://www.highspeed1.com/news/?page=7&id=127

Unlikely the ECML OHLE could be a problem, as it's relatively speaking no nearer than the HS1 OHLE?

It's quite a bit closer! The ECML wires pass right beneath the bridge and will be several feet closer to the HS1 track than it's own 25kV supply. But if an acoustic barrier is the reason given, then the question has been answered - although I'm surprised because the average speed of ECML trains there is faster than the HS1 trains and they'll be more frequent too! Anyway - as I said - we have an answer.

 

[Fred26]

That single track line running from west to north in the picture; is that the line which will see trains from the GN running through to St Pancras?

 

[Nym]

IIRC no, there is a tunnel, just visible at the bottom of frame, about 1/8th of the way across, you can just see the tunnel portal, this is going to be a 2 track link to Platforms A and B, the track hasn't been layed yet though. The track I think you're on about leads to the North London Line, and possibly the domsetic platforms at St P and the E* ones, for reigonal E* up the ECML

 

[kentuckytony]

Thanks all! I guess I wasn't alone in wondering.

 

[caliwag]

Yup noise, I worked on it. Great for the graffiti boys! The glass blocks in the extension are there for the same reason...not some architect's fashion statement...mind if it was, it would be a few decades out of date!!

 

[LE Greys]

There seems to be a second link alongside the portal leading towards the junction with the NLL chord. Is that just an access road or is it a future connection from St Pancras itself to the ECML?

 

[Striker]

There seems to be a second link alongside the portal leading towards the junction with the NLL chord. Is that just an access road or is it a future connection from St Pancras itself to the ECML?

The entrance with no line laid is the tunnel entrance to the future connection from the ECML to the underground Thamslink platforms A and B at St Pancras.

 

[LE Greys]

The entrance with no line laid is the tunnel entrance to the future connection from the ECML to the underground Thamslink platforms A and B at St Pancras.

I meant just west of there.

 

[jopsuk]

That's the chord to St Pancras International (and HS2 domestic) and the North London Line? I think that's what you're referring to anyway. I've uploaded a huge composite image if that helps?

 

[LE Greys]

that's the chord to st pancras international (and hs2 domestic) and the north london line? I think that's what you're referring to anyway. i've uploaded a huge composite image if that helps?

In between the two!!!

Oh, so there's already a direct connection from St Pancras International to the ECML, just no track down, sorry.
Looks like what I was looking at was an access road after all.

 

[route101]

Do any houses feel hear the trains on HS 1 underneath them ?

 

[LucaZone]

Actually that portal is related to ThamesLink, and links to a through station underneath St Pancras:

http://www.martinunderwood.f9.co.uk/Ladykillers/images/large/CTRL lines.gif

Regards