In article
,
(D7666) wrote:

On Jun 7, 10:29*am, dave wrote:

Then there's things like speed control relays that were put in after
Moorgate crash (mostly),

Errr that is misleading.

Speed control relays have been around on LT / LU for eons, they are
nothing new introduced post Moorgate.

Moorgate introduced TETS or whatever its called - Train Entering
Terminal Station - which simply adds more timing relays and more train
stops as any passenger train approach any buffers stops.

Hasn't been superseded by TPWS?

--
Colin Rosenstiel

In article ,
Peter Masson wrote:


"amogles" wrote in message
...
On 6 Jun., 16:58, john wright wrote:


"When there was only one line for the whole of London" What can that
refer to? Neither telephones nor rail lines makes much sense in this
context.

When the various "lines" that now form the London Underground were
built, they were separate railways and were referred to by their
names, ie C&SLR etc. I assume that the practice of calling them lines
must have come in when they were all part of London Underground. Does
anybody know when the term "line" first came into use in this context

'Line' to refer to a railway company was certainly in use by 1895: 'The

By the 1870s, when there was a popular music-hall song in northern pasts
to the effect that:

"He went to Bradford for to dine
By the Lancashire and Yorkshire line
He waited two weeks at bleak Low Moor
And when he complained the porter swore
That he should hace started the month before"

(culled from Ahrons, and certainly applying to the 'old' L&Y
of the pre-1880s period).

--
Andy Breen ~ Not speaking on behalf of the University of Wales, Aberystwyth
Feng Shui: an ancient oriental art for extracting
money from the gullible (Martin Sinclair)

On Jun 7, 2:24*pm, David Hansen
wrote:

Speed control relays have been around on LT / LU for eons, they are
nothing new introduced post *Moorgate.

Holding a signal and/or train stop at danger and only releasing it
if a train operates track circuit(s) in more than a specified time,
thus proving the train is going slowly enough, was certainly done
before the crash at Moorgate. Sharp curves and approaching signals
with a short overlap are examples. Presumably the way the front of
trains used to enter platforms while the rear of the previous train
was leaving [1] is another example. However, this was greatly
extended

I dis-agree, still, with this term ''greatly extended''.

The use of timed relays is and always has been much much much more
extensive than curves and overlaps indeed is the very essence of
headway control across the entire LU network, everywhere, including
plain line with no restrictions. don't try and apply main line
practice ''approach control'' to this, it is very very different. Even
plain line LU automatic signalling is different - there are - in non
signals engineers over simplified terms - 2 track circuits between
every signal for every 1 on main lines. This is fundamental to LU
signalling practice.

The quantity of additional relays for TETS is not that significant.
Baker Street Met IMR for example - a location I have visited several
times for work - is (I think) about the number of fingers of one hand
timed relays for the 2 bays TETS , but there are around a couple of
dozen others (off the top of my head) doing non TETS stuff, to protect
the 2 convergence points (the Met. City junction, and the north end
throat, and always have done.

Edgware Road for example does not have TETS, but it has - and indeed
again always has had - *huge* numbers of timed relays. I've never been
in Edgware Road cabin or relay rooms - much that I'd like too - and
probably will one day legitimately get a professional related visit -
but I travel through the place almost every day and looked up the
signals diagrams to understand it all.

--
Nick






--
Nick

On 07/06/2010 10:45, David Hansen wrote:
On Mon, 7 Jun 2010 02:29:14 -0700 (PDT) someone who may be dave
wrote this:-


What has failed a fair few times is the new electric points at Praed
Street!

Interesting to know. An earlier poster said that it may be new
equipment which is more prone to failure.

I am reminded of the axle counters around the Severn Tunnel which
couldn't cope with sunshine, leading to repeated failures and
eventually a crash which appears to have been caused by the axle
counters being reset without proper precautions (though this cannot
be concluded as the witch-hunt atmosphere of the time (lessened but
not totally gone these days I gather) meant that people are not
likely to admit to mistakes).

Obviously old signalling equipment could and can be affected by the
sun too, but rodding runs have ways of dealing with this and wire
adjusters are provided for signals.



New equipment may very well be more prone to failure because there tends
to be far more to go wrong. There was (in some places still is!) the
old Victorian technology of someone pulling levers connected to wires
connected to signals, also simple telegraph instruments and single
stroke bells to communicate. Compare this with the "black art" of the
modern electronic signalling systems with a maze of processors,
communication links and detection systems which can be the devil's own
game to "troubleshoot".

Add to this the likelihood that any problems may be less obvious to the
users - the old technology could largely be "seen". This is why many
people will go to things like the mechanical organ museum in Norfolk -
you can see the exhibits working and in many cases how they work. In
future years, who is going to go to a museum to watch a board of
integrated circuits sit there?

Don't get me wrong - technology is great and the job I do is so much
better now than with the antiquated kit we used to have to use. But
discretion is required - it is a general rule that the simplest solution
that does the job is also the best one.

New technology should not automatically replace the old - it should give
us more choice. Where the old way is reliable and does the job safely
and efficiently, why throw it away? I have often thought that some of
the older signalling technologies might actually serve the railway
better than going too far down the fancy computer systems road,
precisely because the modern stuff can be too complex and too vulnerable.

Axle counters are a very good example. They are replacing track
circuits because axle counters are allegedly more reliable. But when
someone has on overnight possession [for engineering work], the track
circuits are normally still working in the morning but the axle counters
invariably have to be re-set. This requires either the first train or
two being "talked past" signals to restore the settings, or the whole
system being reset which means nothing moves for a few minutes. And its
not just sunlight - track workers in the Bournemouth area were given
strict instructions not to use mobile phones near the new axle counter
heads because that also confused the signalling.

I'm all for progress - but progress means that the new kit must work
*better* than the old stuff did. If it is harder to use, more difficult
to fault find, breaks down more, and exhibits its own new ways of going
wrong, I'm afraid that's not "progress". I know of more than one modern
system which has been introduced mostly to save on (staff) costs, and if
it actually works better than before (in the case of Network Rail's new
timetable system, if it works at all!), that seems to be a bonus.

--
- Yokel -

Yokel posts via a spam-trap account which is not read

In message
Yokel wrote:

[snip]

Add to this the likelihood that any problems may be less obvious to the
users - the old technology could largely be "seen". This is why many
people will go to things like the mechanical organ museum in Norfolk -
you can see the exhibits working and in many cases how they work. In
future years, who is going to go to a museum to watch a board of
integrated circuits sit there?

[snip]

www.bletchleypark.org.uk/calendar/event_detail.rhtm?cat=special&recID=594620

--
Graeme Wall

This address not read, substitute trains for rail
Transport Miscellany at www.greywall.demon.co.uk/rail
Photo galleries at http://graeme-wall.fotopic.net/

On Tue, 08 Jun 2010 10:51:45 +0100 someone who may be Yokel
wrote this:-

In
future years, who is going to go to a museum to watch a board of
integrated circuits sit there?

While I agree with much of your post, there are already examples of
old computer equipment on display in museums. It is often a
non-working exhibit, but there are examples of working exhibits,
Bletchley Park being the best known example.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000...#pt3-pb3-l1g54

On Tue, 08 Jun 2010 11:58:16 +0100
David Hansen wrote:
On Tue, 08 Jun 2010 10:51:45 +0100 someone who may be Yokel
wrote this:-

In
future years, who is going to go to a museum to watch a board of
integrated circuits sit there?

How is that any different to looking at a load of baked clay?

While I agree with much of your post, there are already examples of
old computer equipment on display in museums. It is often a
non-working exhibit, but there are examples of working exhibits,
Bletchley Park being the best known example.

Theres some in the science museum but its a pretty half hearted effort.
The difference engine replica is worth seeing though.

B2003

In message
d wrote:

On Tue, 08 Jun 2010 11:58:16 +0100
David Hansen wrote:
On Tue, 08 Jun 2010 10:51:45 +0100 someone who may be Yokel
wrote this:-

In
future years, who is going to go to a museum to watch a board of
integrated circuits sit there?

How is that any different to looking at a load of baked clay?

While I agree with much of your post, there are already examples of
old computer equipment on display in museums. It is often a
non-working exhibit, but there are examples of working exhibits,
Bletchley Park being the best known example.

Theres some in the science museum but its a pretty half hearted effort.
The difference engine replica is worth seeing though.


Given it is the first one actually constructed, is it really a replica?

--
Graeme Wall

This address not read, substitute trains for rail
Transport Miscellany at www.greywall.demon.co.uk/rail
Photo galleries at http://graeme-wall.fotopic.net/

On 7 June, 15:45, Michael Bell wrote:
In message
ups.com
* * * * * amogles wrote:

On 6 Jun., 16:58, john wright wrote:

"When there was only one line for the whole of London" What can that
refer to? Neither telephones nor rail lines makes much sense in this
context.
When the various "lines" that now form the London Underground were
built, they were separate railways and were referred to by their
names, ie C&SLR etc. I assume that the practice of calling them lines
must have come in when they were all part of London Underground. Does
anybody know when the term "line" first came into use in this context

There was a very interesting early history book about the London
Underground called "Rails through the clay" by Croombe and Jackson,

More recently, I was impressed with Christian Wolmar's book "the
subterranean railway" which is a little more focussed on the economic,
political and social aspects rather than the technological, but he
certainly gives Yerkes some good coverage.

which recounted how an American tycoon called Yerkes, who was a bit of
a wide boy, but he also funded the biggest astronomical telescope of
his day and had it called after himself, built the nucleus of the
London Underground. It was originally going to be cable-hauled, hence
the low profile. They were all nominally separate "lines" (an American
term) though in fact all owned by Yerkes, and he also introduced the
terms "northbound" and "southbound" to indicate direction of travel,
which also have more an American sound than British.

Now hang on a moment here, there are several independent events all
being conflated into one.

First of all, the only cable hauled line actually built was the Tower
Subway, which was the first "deep bore" tube line, with a very small
tunnel diameter indeed, and it did not last long, in part due to the
opening of Tower Bridge.

The same promoter who did the Tower Subway then came up with a more
ambitious project linking the City with suburbs in South London, hence
the name "City and South London Railway". It was planned to use
larger tunnels than the Tower Subway (large enough that standard gauge
track would fit), though still smaller than the current "tube" size.
During construction, the decision was taken to install electric
traction with locomotives rather than cable haulage. The design of
the northern terminus, at King William Street had been made with cable
haulage in mind, and the station was not well suited to electric
operation, so the opportunity was taken when the line was extended
northwards to replace it with a more suitable station at Bank.

By the time Yerkes[1] came on the scene, the C&SLR, Waterloo and City
and Central London Railway were all already operating [2], with
different tunnel sizes and different electrification schemes. Yerkes
bought the Metropolitan District, and bought a whole bunch of the
schemes for underground railways that had received parliamentary
approval after the success of the C&SLR, but had no money. He
consolidate these into three railway companies: the Great Northern,
Picadilly and Brompton Railway; the Charing Cross, Euston and
Hampstead Railway; and the Baker Street and Waterloo Railway.
Although each of these three, and the MDR, were run as separate
companies, they were built to a common design, with the same
electrification system (in the case of the MDR, only the
electrification was the same).

At this point, there are 6 tube lines, three in the Underground Group,
one a subsidiary of the LSWR, and two independent. The Underground
Group rectified this by buying the C&SLR and CLR, and converting them
to Yerkes standard [3]. The other important thing that the
Underground Group did was to introduce interavailable tickets and
single unified branding. Both Yerkes, and Albert Stanley (later Lord
Ashfield) both brought a significant amount of American terminology
and ideas to the Underground Group, I don't think the use of "line"
was one of them.

[1] having first encountered this interesting character in print, I
wondered for the longest time whether his name should be pronounced
"yerks" (to rhyme with jerks) or "yerkees" (to rhyme with turkeys). I
have since been told be someone I am prepared to trust in the matter
that the second option is the correct one.
[2] I can't remember off the top of my head when the Norther City line
opened, but it may also have been around pre-Yerkes.
[3] imperfectly in the case of the Central line, where the outer
conductor rail is a bit higher than on other lines because of the way
the tunnel linings were expanded.

Robin

"bob" wrote

[2] I can't remember off the top of my head when the Norther City line
opened, but it may also have been around pre-Yerkes.

Great Northern & City incorporated 1892, construction started 1898, opened
1904 (i.e after Yerkes had taken control of Underground Electric Railways.
The GN&C was independent, though with links to the Great Northern, until it
was taken over by the Metropolitan in 1913. It was operated with main line
sized trains until 1939, after which it became an isolated part of the
Northern Line, until it was transferred to BR for the Great Northern
Electrics in 1976. As part of the Northern Line, the line from Drayton Park
via Finsbury Park and Highgate to East Finchley was used for stock exchange
(dragged) until it was taken out of use, after which stock exchange took
place via Kings Cross and the Widened Lines, crossing to the Circle Line at
Farringdon.

Peter