On 16 Nov 2019 01:05:17 GMT, Marland
wrote:

Bryan Morris wrote:
In message , Bryan Morris
writes
In message , Roland Perry
writes
In message , at 20:41:41 on Fri, 15 Nov
2019, remarked:
On Fri, 15 Nov 2019 15:17:03 +0000
Roland Perry wrote:
In message , at 14:24:18 on Fri, 15 Nov
2019, Bryan Morris remarked:

I find the Picc unbearably deep, so by the time I've reached Barons
Court (westbound) I'm standing by the door gasping for fresh air. No
other tunnel affects me like that, not even the Chunnel.

I thought the Northern Line Edgware Branch was deepest. I know when I
used to travel via Hampstead/Golders Green my ears used to pop.

That's the deepest under the surface, but the surface is a hill! Air
pressure on the surface there will be lower as a result, by about 2.5%

I think the deepest below sea level (from memory) is the Jubilee between
Westminster and Waterloo.

Later: Hampstead Station is approx 200m above sea level at the surface,
140m above sea level at the platform.

Not it isn't. The highest point of the heath which is well above the tube
station is 134m. I'm guessing the station entrance is around 80-90m.

That's what one gets for looking things up at what turns out to be an
unreliable source. I still believe that the platforms are 60m below
the surface, which a more reliable source puts at 376ft (ie 115m).

Hampstead is on a steep hill and the station platforms are the deepest
on the London Underground network, at 58.5 metres (192 ft) below ground
level. It has the deepest lift shaft on the Underground at 55 metres
(180 ft) which houses high-speed lifts.
Source https://en.wikipedia.org/wiki/Hampstead_tube_station

BTW - I used to live in Highgate and frequently travelled Hampstead
Lane/Heath Street to my office . Hampstead station is not at the top of
the Hill (I might be wrong but it's the Pond by the Heath that's
probably the apex) so the line is further under ground there than at the
station.

Isn’t the deepest bit near the site of the unfinished North End Station now
better known by the unofficial name Bull and Bush?

Apparently, the deepest below sea level are the Jubilee Line platforms
at Waterloo station, 26m down. See this display I photographed at an
exhibition at the LMA:
https://www.flickr.com/photos/recliner/49074038572/in/dateposted-friend/lightbox/

It's a small, but surprisingly interesting exhibition, which runs for
just under another three weeks, well worth a visit if you're in the
area:
https://www.cityoflondon.gov.uk/things-to-do/london-metropolitan-archives/news-events/Pages/under-ground-london.aspx

Basil Jet wrote:
On 15/11/2019 14:24, Bryan Morris wrote:
In message , Basil Jet
writes
On 09/11/2019 17:09, wrote:
Well until we see a crossrail timetable there's no way to tell, but
having
commuted all the way to hatton cross and back each day for 9 months
on that
line I would be very surprised if it was the same end to end. It is
utterly
hopeless especially in the rush hour - it literally crawls through
west london
and only once past hammersmith does it reach anything approaching a
reasonable
speed. And then there'd usually be some pointless delay at Acton. I
actually
terminated the contract early because I couldn't stand it any longer,
almost
2 hours each way door to door on a bad day (which was most of them).

I find the Picc unbearably deep, so by the time I've reached Barons
Court (westbound) I'm standing by the door gasping for fresh air. No
other tunnel affects me like that, not even the Chunnel.

I thought the Northern Line Edgware Branch was deepest. I know when I
used to travel via Hampstead/Golders Green my ears used to pop.

I thinks it's the duration spent at deep level which causes my drowning
feeling. It's only if I go all the way from Bounds Green or so to Barons
Court that it happens.


The Northern and Victorua line tunnels are longer, of course, but perhaps
you don't travel through them?

In article , Roland Perry
writes
I thought the Northern Line Edgware Branch was deepest. I know when I
used to travel via Hampstead/Golders Green my ears used to pop.

That's the deepest under the surface, but the surface is a hill! Air
pressure on the surface there will be lower as a result, by about 2.5%

I think the deepest below sea level (from memory) is the Jubilee between
Westminster and Waterloo.

Based on a 2015 FOI request, the following platforms are at least 15
metres below sea level (numbers are metres above LU datum, which is
exactly 100 metres below the OS datum at Newlyn):

74.0 Waterloo (Jubilee)
74.6 Westminster (westbound Jubilee)
76.8 London Bridge (Jubilee)
79.5 Southwark
80.2 Elephant & Castle (Bakerloo)
80.4 London Bridge (Northern)
81.9 Charing Cross (Jubilee)
81.9 Holborn (westbound Piccadilly)
82.8 Waterloo (Northern)
83.5 South Kensington (westbound Piccadilly)
83.9 Pimlico
84.0 Westminster (eastbound Jubilee)
84.4 Canary Wharf (Jubilee)
84.4 Kennington (City branch)
84.4 Bank (Northern)
84.6 Kennington (Charing X branch)
84.6 Elephant & Castle (northbound Northern)
84.7 Elephant & Castle (southbound Northern)

--
Clive D.W. Feather

In message , at 14:48:05 on
Sat, 16 Nov 2019, Recliner remarked:

Isn’t the deepest bit near the site of the unfinished North End Station now
better known by the unofficial name Bull and Bush?

Apparently, the deepest below sea level are the Jubilee Line platforms
at Waterloo station, 26m down.

There's an echo in here.
--
Roland Perry

On Sat, 16 Nov 2019 14:48:05 +0000
Recliner wrote:
https://www.flickr.com/photos/reclin...-friend/lightb
ox/

I wonder why the water tunnels are so deep. You'd think when pumping water
around you'd want them to be as shallow as possible since water is heavy stuff
and requires huge amounts of energy to pump back uphill.

On Sat, 16 Nov 2019 16:19:01 +0000
"Clive D.W. Feather" wrote:
Based on a 2015 FOI request, the following platforms are at least 15
metres below sea level (numbers are metres above LU datum, which is
exactly 100 metres below the OS datum at Newlyn):

*Above* the LU datum? Why did they choose something so deep as a base point?

74.0 Waterloo (Jubilee)
84.4 Bank (Northern)

Looks like the actual deepest railway platform in London is a toss up between
jubilee waterloo and Bank DLR which is way beneath the northern line platforms.
Anyone know how deep the DLR is?

On 17/11/2019 09:08, wrote:
On Sat, 16 Nov 2019 16:19:01 +0000
"Clive D.W. Feather" wrote:
Based on a 2015 FOI request, the following platforms are at least 15
metres below sea level (numbers are metres above LU datum, which is
exactly 100 metres below the OS datum at Newlyn):

*Above* the LU datum? Why did they choose something so deep as a base point?

I don't know for a fact when and why that was done for the tube but
shifting the zero on a scale was a recognised way of reducing the scope
for errors such as a typo that omits a "-" or a reader missing a "-";
and -13.2 minus -17.4 resulting in -4.2. Especially before VisiCalc,
SuperCalc etc.

--
Robin
reply-to address is (intended to be) valid

On 17/11/2019 09:04, wrote:
On Sat, 16 Nov 2019 14:48:05 +0000
Recliner wrote:
https://www.flickr.com/photos/reclin...-friend/lightb
ox/

I wonder why the water tunnels are so deep. You'd think when pumping water
around you'd want them to be as shallow as possible since water is heavy stuff
and requires huge amounts of energy to pump back uphill.


The problem with that diagram is that it shows depth below ground level,
not sea level (or river level in this case), so it gives a distorted
view of the actual depths.

One possible reason for a deep water tunnel is to give it a straight run
so you don't have to keep pumping water uphill at intermediate points on
the route.

--
Graeme Wall
This account not read.

Graeme Wall wrote:
On 17/11/2019 09:04, wrote:
On Sat, 16 Nov 2019 14:48:05 +0000
Recliner wrote:
https://www.flickr.com/photos/reclin...-friend/lightb
ox/

I wonder why the water tunnels are so deep. You'd think when pumping water
around you'd want them to be as shallow as possible since water is heavy stuff
and requires huge amounts of energy to pump back uphill.


The problem with that diagram is that it shows depth below ground level,
not sea level (or river level in this case), so it gives a distorted
view of the actual depths.

One possible reason for a deep water tunnel is to give it a straight run
so you don't have to keep pumping water uphill at intermediate points on
the route.


The tideway tunnel needs to be below both existing sewage/storm water
tunnels and the under-river rail tunnels, such as the deep Jubilee tunnels
near Waterloo. With current tunneling techniques, they don't need to stay
in the clay layer, and nor do they have to build watertight underground
stations, so they might as well go deep.

On Sun, 17 Nov 2019 09:40:54 +0000
Graeme Wall wrote:
On 17/11/2019 09:04, wrote:
On Sat, 16 Nov 2019 14:48:05 +0000
Recliner wrote:

https://www.flickr.com/photos/reclin...-friend/lightb

ox/

I wonder why the water tunnels are so deep. You'd think when pumping water
around you'd want them to be as shallow as possible since water is heavy
stuff
and requires huge amounts of energy to pump back uphill.


The problem with that diagram is that it shows depth below ground level,
not sea level (or river level in this case), so it gives a distorted
view of the actual depths.

One possible reason for a deep water tunnel is to give it a straight run
so you don't have to keep pumping water uphill at intermediate points on
the route.

Makes sense. Even so, I dread to think how much electricity the pumping must
require. Probably a small power stations worth.