Tunnel crossing of the WCML and Metropolitan line, by Swiss Cottage and South Hampstead stations

[Anstecker]

The Metropolitan line crosses over the WCML at Swiss Cottage, just east of South Hampstead Overground station (51.541812, -0.175286). Both lines are in tunnel at this point, with the WCML underneath and built first, and the whole assemblage is underneath Finchley Road.

I've found it surprisingly hard to find information about what must have been a complex piece of construction; there's nothing about it in Alan A. Jackson's book. Are the tunnels structurally separated by earth, or is it built as one giant assemblage? Has it ever been reconstructed, and can it be identified from track level? Many thanks for any information.

 

[eastwestdivide]

Are they both in tunnel there? The OS map shows a bridge right by three tunnel mouths - bing maps OS version here:

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[Supercoss]

The wcml is in Prinrose Hill Tunnel , seperate slow line and fast line bores with the " DC" new line ( overground Euston-Watford Line )in a further bore to East called South Hampstead Tunnels .
Above the North Portal , just by the Euston end of South Hampstead station, the Chiltern Mainline crosses , popping out into open on a bridge over wcml from St Johns wood Tunnel on west side ( towards Marylebone) before going in to a further smaller tunnel Hampstead Tunnel on east side (towards Finchley Road)
the Metroploitan line tube is fully sub surface in this " crossroads" and not visible being in a tunnel from FinchleyRoad

 

[Gloster]

The bridge just west of the tunnel mouth is the GC/Chiltern line and the Met is over the top of the LNWR tunnel. I am no civil engineer, but I presume that there are effectively bridges constructed over the LNWR tunnels, with the bridge abutments replacing part of the LNWR tunnel wall. It doesn’t look as though the Met could pass well clear above the LNWR.

 

[Magdalia]

The wcml is in Prinrose Hill Tunnel , seperate slow line and fast line bores with the " DC" new line ( overground Euston-Watford Line )in a further bore to East called South Hampstead Tunnels .
Above the North Portal , just by the Euston end of South Hampstead station, the Chiltern Mainline crosses , popping out into open on a bridge over wcml from St Johns wood Tunnel on west side ( towards Marylebone) before going in to a further smaller tunnel Hampstead Tunnel on east side (towards Finchley Road)
the Metroploitan line tube is fully sub surface in this " crossroads" and not visible being in a tunnel from FinchleyRoad

The compass points are all wrong here, which makes it very confusing.

Above the North Portal , just by the Euston end of South Hampstead station

At this point the line out of Euston is running from east to west, so this should read west portal.

popping out into open on a bridge over wcml from St Johns wood Tunnel on west side ( towards Marylebone)

At this point the line out of Marylebone is running from south to north, so towards Marylebone is on the south side of the WCML.

before going in to a further smaller tunnel Hampstead Tunnel on east side (towards Finchley Road)

and towards Finchley Road is on the north side of the WCML.

 

[Supercoss]

Simply look at it as

(N)
Watford
South Hampstead
(W) Marylebone Finchley Road (E)
Euston
(S)

for the purpose of a forum discussion without graphics

 

[Magdalia]

Simply look at it as

(N)
Watford
South Hampstead
(W) Marylebone Finchley Road (E)
Euston
(S)

for the purpose of a forum discussion without graphics

I suggest that you look at a map. For the purposes of a forum discussion without graphics it is even more important to get it right.

(N)
Finchley Road
(W) Willesden Jn-South Hampstead-Primrose Hill (E)
Marylebone
(S)

 

[Supercoss]

Wcml running North South
Chiltern Mainline running East West
for ease of explaining original post On crossing at South Hampstead

 

[TheDavibob]

Image courtesy of Carto Metro for context.

Interestingly, it thinks the Met passes under the WCML here, though it might be wrong. I think using real compass directions here makes things easier, but that might just be me!

 

[Magdalia]

View attachment 136075View attachment 136076
Wcml running North South
Chiltern Mainline running East West
for ease of explaining original post On crossing at South Hampstead

That is upside down and has no indication of which direction is north. It does not follow the usual convention of having north at the top.

Image courtesy of Carto Metro for context.

Interestingly, it thinks the Met passes under the WCML here, though it might be wrong. I think using real compass directions here makes things easier, but that might just be me!

Thanks.

It is perhaps worth pointing out that Willesden Junction is on almost exactly the same latitude as Euston, hence almost due west, and only a short distance away from the GWR route out of Paddington.

For understanding the railway geography of the area it is essential to appreciate that the WCML is an east-west railway between Primrose Hill and Willesden Junction.

There is a similar issue with the Midland Main Line, which runs east-west between Kentish Town and West Hampstead, in consequence crossing the North London Line 3 times.

 

[LNW-GW Joint]

Before long there will be another tunnel running through that area - HS2, assuming the Euston tunnels from Old Oak Common get built.
They will be more or less under the WCML alignment, with ventilation shafts at Adelaide Road (east of Primrose Hill tunnel) and at Canterbury Works (between Kilburn High Road and Queen's Park stations).

 

[DelW]

I don't know any details about the specific location, but there are examples where there is insufficient vertical clearance and so a section of the lower line's tunnel crown is omitted to allow the upper track to cross on a conventional bridge. One such is where the Tonbridge to Redhill line crosses the Uckfield line northwest of Edenbridge. It can be seen in the Google satellite and Streetview views:


Though it would be more complicated if the upper line was also in tunnel, as apparently at South Hampstead.

 

[Basil Jet]

While the Met is not visible where it crosses the WCML, it is visible just to the north as a long slit in the pavement on the west side of Finchley Road (the road) opposite Eton Avenue. Confusingly this air hole has a roundel perched above it, making it look like a staircase to a tube station, but the staircase to the Jubilee station is actually a few metres further west. The Met is also visible just to the south of the WCML at the old Marlborugh Road station on the corner of Queens Grove and Finchley Road.

 

[Anstecker]

Many thanks for the replies. Yes, the double tunnel (what do you call it?) is entirely underground, underneath the road. The GCML running to the west emerges from tunnel to cross on a bridge, but the Met is entirely underground.

I hadn't seen that Carto Metro thinks that the metropolitan line travels underneath the WCML. That's wrong, it doesn't go anything like deep enough. The cuttings nearby are much shallower. And the NLS website shows an 1868 OS map from just after the Metropolitan line was built which shows it on top.

Now I think about it, the structure actually has been rebuilt as the WCML has expanded: twice in fact, once when the WCML went to four tracks though the tunnel, by 1895, and then in the early twentieth century when it was six-tracked. All in all, I'm surprised not more has been published about it. I can't think of any other structure like it.

 

[Taunton]

I can't think of any other structure like it.

There are a whole range across Liverpool, although one level often now abandoned. The old CLC approach to Liverpool Central, still in use, had two such in separate tunnels, one where it crossed the Liverpool Overhead Railway (in tunnel) at Dingle, the other where it crossed the old LNWR tunnel to Crown Street goods nearer to Central station. There are others around the city.