"David Spiro" wrote in message
...
"Tom Anderson" wrote in message
h.li...
I don't know that this was easier to
achieve due to the cut-and-cover method, or simply was a brilliant idea at
the time.

It's most definitely a better way of doing things, but prohibitively
expensive when drilling tunnels. With cut-and-cover, you just make your
trench a bit wider. With deep-level tunnels, you have to dig twice as many
tunnels.

On Thu, 18 Aug 2005 15:27:52 +0100, Tom Anderson
wrote:

(i assume because digging wide deep tunnels was ruinously expensive).

I suspect so. A modern equivalent, the Merseyrail Loop, is very
nearly[1] full mainline loading gauge because modern tunneling
equipment made it rather easier.

[1] PEP-derived EMUs, e.g. 508s, fit, but not the slightly larger
Mk3-derived units like 455s, as I recall. The structure gauge
difference can be seen quite nicely in those 455s that have a spare
508 car inserted. Not enough to have a major impact on passenger
comfort or internal layout, but enough to be visible.

Neil

--
Neil Williams in Milton Keynes, UK
When replying please use neil at the above domain
'wensleydale' is a spam trap and is not read.

On 18 Aug 2005 08:43:27 -0700, "Joe Patrick"
wrote:

There are some fast and semi-fast trains on the underground, though
only on the Metropolitan line north of Harrow-on-the-Hill, and not on
the Uxbridge services.

Also, effectively, on the shared section between the District and
Piccadilly lines towards Heathrow.

They are designated as different lines, but the principle is not
really any different.

Neil

--
Neil Williams in Milton Keynes, UK
When replying please use neil at the above domain
'wensleydale' is a spam trap and is not read.

In message , Tom
Anderson writes
Conversely, London never had the el-to-subway transition that built a
lot of the NYC system (there are one or two examples of this happening
in London, though).

I'll probably kick myself when you answer this.......but where are there
any examples of this happening in London?
--
Ian Jelf, MITG
Birmingham, UK

Registered Blue Badge Tourist Guide for London and the Heart of England
http://www.bluebadge.demon.co.uk

On Thu, 18 Aug 2005, Ian Jelf wrote:

In message , Tom Anderson
writes

Conversely, London never had the el-to-subway transition that built a
lot of the NYC system (there are one or two examples of this happening
in London, though).

I'll probably kick myself when you answer this.......but where are there
any examples of this happening in London?

There aren't - what i was thinking of, but didn't say, was surface-running
to underground transitions. Sorry!

As for that, i believe that some of the sub-surface network (i thought it
was the northern side of the Circle but can't find any evidence for that)
were built at or near ground level, for the use of steam engines, but when
electric trains became available, it was rebuilt underground (presumably
so the land on top could be built on).

It's possible i'm imagining this, though.

tom

--
On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question. -- Charles Babbage

On Thu, 18 Aug 2005, Martin Underwood wrote:

"Tom Anderson" wrote in message
h.li...
On Thu, 18 Aug 2005, David Spiro wrote:

Another interesting difference is the almost complete lack of
underground line in south London - here, the suburban surface rail
network was very well-developed early on (and extensive urbanisation
was later than in the north, i think), so the need for tubes never
arose. I don't know if there's a a parallel in New York - are there any
boroughs with surface rail lines rather than subways?

I thought one of the reasons that there are very few tube lines south of
the Thames is that the geology is different and doesn't lend itself to
tunnelling - except around Crystal Palace where the Sydenham tunnels are
through rock that is easier to tunnel through.

Yes, i've heard that too, but i think it's an urban myth. We've gone over
it here before; google groups might be able to turn up more info.

tom

--
On two occasions I have been asked [by members of Parliament], 'Pray, Mr.
Babbage, if you put into the machine wrong figures, will the right answers
come out?' I am not able rightly to apprehend the kind of confusion of
ideas that could provoke such a question. -- Charles Babbage

On Thu, 18 Aug 2005, Neil Williams wrote:

On Thu, 18 Aug 2005 15:27:52 +0100, Tom Anderson
wrote:

(i assume because digging wide deep tunnels was ruinously expensive).

I suspect so. A modern equivalent, the Merseyrail Loop, is very
nearly[1] full mainline loading gauge because modern tunneling
equipment made it rather easier.

[1] PEP-derived EMUs, e.g. 508s, fit, but not the slightly larger
Mk3-derived units like 455s, as I recall. The structure gauge
difference can be seen quite nicely in those 455s that have a spare
508 car inserted. Not enough to have a major impact on passenger
comfort or internal layout, but enough to be visible.

I'm afraid i don't know my PEP from my Mk3; do you mean that the tunnels
are smaller than W6A gauge? Or are these Mk3 things bigger than W6A?
Building a tunnel infinitesimally smaller than the standard loading gauge
seems like the height of madness - for a negligable saving, you throw away
the ability to every kind of passenger train, present and (near) future,
without worrying about the details of its size!

tom

--
On two occasions I have been asked [by members of Parliament], 'Pray, Mr.
Babbage, if you put into the machine wrong figures, will the right answers
come out?' I am not able rightly to apprehend the kind of confusion of
ideas that could provoke such a question. -- Charles Babbage

On Thu, 18 Aug 2005, David Spiro wrote:

"Tom Anderson" wrote in message
h.li...

Another interesting difference is the almost complete lack of
underground line in south London - here, the suburban surface rail
network was very well-developed early on (and extensive urbanisation
was later than in the north, i think), so the need for tubes never
arose. I don't know if there's a a parallel in New York - are there any
boroughs with surface rail lines rather than subways?

Well, in the Bronx where I grew up, some of the lines, such as the #6
are almost completely above ground, though it does go under for about
the last quarter of it's journey before going into Manhattan, which is
completely below ground. The only other line that I am familiar with
that is just about all above ground is the #7 Flushing line train, which
only goes below ground at its eastern terminus at Main Street in
Flushing. On the whole, the system is a mix of both above and below
ground service. Even in Manhattan, the #1 Broadway local train is on an
elevated section through a part of Harlem, the last elevated subway in
Manhattan, albeit for a short stretch.

I see. I guess the difference is that the subway and above-ground bits
were built by the same companies, as two ways of building lines, as
necessary. In London, we had one lot building mixed lines in the north,
and another lot building purely above-ground lines in the south - the
distinction survives today, as the lines are operated by entirely
different organisations.

In fact, the really important distinction between north London's
underground and south London's railways is not their altitude, but their
topology: underground lines usually consist of a central section with one
or two limbs at each end, so they can easily run a high-frequency service;
the railways, however, generally have many more branches, and interconnect
into a complex network, making it impossible to deliver high frequencies
at the outer ends. I have no idea why it worked out like that; perhaps
because it's so much easier to add branches to an existing surface line
than it is to add onto a tube. Socio-economic factors are probably also in
there somewhere.

Also, of course, the underground lines all run under the centre, whereas
the railways all stop at termini just outside the city centre (apart from
Thameslink). You might think that's a physical thing - after all, you can
hardly drive surface railways through central London - but the thing is,
there are north London surface railways (there are a handful of these;
it's not all tubes!) that did it. The Great Northern & City railway
planned to do it as early as 1891 (although it didn't _quite_ happen until
the 1970s!), and around the time of the first world war, the London &
North Western Railway managed to hook its line up to the Bakerloo tube
line. Now, the southern end of that line is at Elephant & Castle, which is
pretty close to a number of southern railway routes, so i really don't
understand why none of those were joined up to it.

tom

[1] Or whatever it's called - Great Northern Electrics, Northern City
line, Moorgate line, etc.

--
On two occasions I have been asked [by members of Parliament], 'Pray, Mr.
Babbage, if you put into the machine wrong figures, will the right answers
come out?' I am not able rightly to apprehend the kind of confusion of
ideas that could provoke such a question. -- Charles Babbage

On Thu, 18 Aug 2005, Neil Williams wrote:

On 18 Aug 2005 08:43:27 -0700, "Joe Patrick"
wrote:

There are some fast and semi-fast trains on the underground, though
only on the Metropolitan line north of Harrow-on-the-Hill, and not on
the Uxbridge services.

Also, effectively, on the shared section between the District and
Piccadilly lines towards Heathrow.

They are designated as different lines, but the principle is not
really any different.

Indeed. Perhaps the confusion in NYC could be avoided simply by changing
the names of the lines!

tom

--
On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question. -- Charles Babbage

wrote in message
oups.com...
Ironically although it is called the London Underground it has more
miles of track on the surface. Is this the same with the New York
Subway?

Not anymore. Far more of it is underground than above ground these days, at
least to my knowledge.