WHy is the central line so much faster?
 

Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

B2003

WHy is the central line so much faster?
 

On Feb 11, 7:17*pm, Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

B2003

I guess it's to do with what's allowed with automatic operation.

Any higher speed was mitigated for years by the fact that the
operators seemed to take about thirty seconds to release the doors at
every station. They seem to have got better at it now.

WHy is the central line so much faster?
 

"MIG" wrote in message
...
On Feb 11, 7:17 pm, Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

B2003

I guess it's to do with what's allowed with automatic operation.

Any higher speed was mitigated for years by the fact that the
operators seemed to take about thirty seconds to release the doors at
every station. They seem to have got better at it now.

The announcements are still way off sometimes. Half way out the station and
they are still saying what station it is.

WHy is the central line so much faster?
 

MIG wrote:
On Feb 11, 7:17 pm, Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison?

I guess it's to do with what's allowed with automatic operation.

The Victoria line is pretty fast too, for the same reason
--
Michael Hoffman

WHy is the central line so much faster?
 

Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

The Met main line, late at night, is hardly known for its sluggishness. I've
been on post-midnight trains, many times, and been hanging on for dear life
to anything that was fixed, especially between Finchley Road and Moor Park!

WHy is the central line so much faster?
 

"Michael Hoffman" wrote in message
...
MIG wrote:
On Feb 11, 7:17 pm, Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison?

I guess it's to do with what's allowed with automatic operation.

The Victoria line is pretty fast too, for the same reason

Trains on Piccadilly line seem to do pretty well speedwise between
Hammersmith and Acton Town.

And what about trains running fast on the Metropolitan Line? I heard that
the A62s could do close to 70 miles before they started to discover cracks
in the bogies.

What's up with the S stock, BTW? 'Any models running around for testing yet?

WHy is the central line so much faster?
 

On 11 Feb, 22:16, wrote:
"Michael Hoffman" wrote in message
The Victoria line is pretty fast too, for the same reason

It is not, it just makes a lot of noise. I was shocked to discover the
leisurely Gospel Oak to Barking line does a similar length journey in
the same time, with only slightly fewer stops.

Diamond Geezer has a handy chart:
http://diamondgeezer.blogspot.com/20...76561523894676

What's up with the S stock, BTW? 'Any models running around for testing yet?

They've only just started building the first couple of carriages:
http://www.districtdave.proboards39....e=4#1201372611

U

--
http://londonconnections.blogspot.com/
A blog about transport projects in London

WHy is the central line so much faster?
 

Mr Thant wrote:
On 11 Feb, 22:16, wrote:
"Michael Hoffman" wrote in message
The Victoria line is pretty fast too, for the same reason

It is not, it just makes a lot of noise. I was shocked to discover the
leisurely Gospel Oak to Barking line does a similar length journey in
the same time, with only slightly fewer stops.

Diamond Geezer has a handy chart:
http://diamondgeezer.blogspot.com/20...76561523894676

Hmmm, I am unconvinced by the average speed over the whole line. The
Central and especially the Metropolitan line have long non-stop expanses
which would certainly help the overall speed, but not the speed in
central London with lots of stops.

But on reading the original post more carefully, it seems Boltar is
discussing the speed in nonstop areas so this is not relevant.
--
Michael Hoffman

WHy is the central line so much faster?
 

On Feb 11, 7:17 pm, Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

B2003

Yeah! I normally use the Northern or District, but I was on the
Central the other day and it went like a rocket. However, I've heard
that London Bridge-Southwark (Jubilee) is the fastest piece of track.

WHy is the central line so much faster?
 

On Feb 11, 10:10*pm, "Jack Taylor" wrote:
Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

The Met main line, late at night, is hardly known for its sluggishness. I've
been on post-midnight trains, many times, and been hanging on for dear life
to anything that was fixed, especially between Finchley Road and Moor Park!

The Central Line used to seem to really move at the other far end,
mainly heading south (west if someone insists) from Theydon Bois to
Debden and also between Epping and North Weald.

Then again, 1962 stock was so bouncy even at low speeds that maybe it
just seemed fast. Don't often go that way these days.

WHy is the central line so much faster?
 

"Boltar" wrote in message

Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

I'm guessing that the 1992 stock has the highest power to weight ratio
of all LU trains. It's also the only stock to have every axle motored.
Do any other British trains (including main line) have this?

WHy is the central line so much faster?
 

"Offramp" wrote in message
...
On Feb 11, 7:17 pm, Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

B2003

Yeah! I normally use the Northern or District, but I was on the
Central the other day and it went like a rocket. However, I've heard
that London Bridge-Southwark (Jubilee) is the fastest piece of track.


In the case of both Northern and District, I suspect station spacing will
have a lot to do with it. Travelling on the Northern line often feels so
painfully slow because it's constantly stopping. Stations on the Vic are
further apart, so trains spend less time stopping, and are able to get a
slightly greater speed up during the long stretches.

The Central line benefits from rising/falling gradients on the approaches to
its stations in town, which means that trains will accelerate quickly when
leaving a station.

BTN

WHy is the central line so much faster?
 

On Feb 12, 10:50*am, "Recliner" wrote:
"Boltar" wrote in message

Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

I'm guessing that the 1992 stock has the highest power to weight ratio
of all LU trains. It's also the only stock to have every axle motored.
Do any other British trains (including main line) have this?

I think it may have been the case with the old District Line R stock.
That always seemed to out-accelerate the 1962 stock at Mile End (but
maybe only from 0 - 5 mph).

WHy is the central line so much faster?
 

"MIG" wrote in message

On Feb 12, 10:50 am, "Recliner" wrote:
"Boltar" wrote in message


Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I
did it last year. Why is the central line different?

I'm guessing that the 1992 stock has the highest power to weight
ratio
of all LU trains. It's also the only stock to have every axle
motored.
Do any other British trains (including main line) have this?

I think it may have been the case with the old District Line R stock.
That always seemed to out-accelerate the 1962 stock at Mile End (but
maybe only from 0 - 5 mph).

Yes, I think the R Stock did have all axles powered, though I suspect
that the power to weight ratio of a train from 60 years ago would have
been less.

WHy is the central line so much faster?
 

On 12 Feb, 10:50, "Recliner" wrote:
"Boltar" wrote in message

Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

I'm guessing that the 1992 stock has the highest power to weight ratio
of all LU trains. It's also the only stock to have every axle motored.
Do any other British trains (including main line) have this?


Good point, I'd forgotten about that. Wonder why they didn't insist on
it for the jubilee and northern stock since the northern line trains
seem pretty sluggish in all departments. Their acceleration is woeful
and they seem to have a top speed of about 30mph.

B2003

WHy is the central line so much faster?
 

On 12 Feb, 00:47, Michael Hoffman wrote:
But on reading the original post more carefully, it seems Boltar is
discussing the speed in nonstop areas so this is not relevant.

That's kind of the point though. Even with few stations and very
aggressive acceleration, the average journey time on the Victoria is
mediocre, so I can only conclude the cruising speed is not as high as
it seems.

U

--
http://londonconnections.blogspot.com/
A blog about transport projects in London

WHy is the central line so much faster?
 

On Feb 12, 9:37 pm, Mr Thant
wrote:
That's kind of the point though. Even with few stations and very
aggressive acceleration, the average journey time on the Victoria is
mediocre, so I can only conclude the cruising speed is not as high as
it seems.

Could the figures be distorted by the Victoria Line not extending
outside Zone 4?

All other things being equal, I would expect the average speed of a
train in Zone 1to be slower than that of a train in Zone 6. To some
extent this should be balanced by the Victoria Line having less
stations than a typical line in Zone 1, anyway, but comparisons of
average speed within zone 1 would be more valid.

--
Abi

WHy is the central line so much faster?
 

In article ,
_dot_uk (Recliner) wrote:

"MIG" wrote in message

On Feb 12, 10:50 am, "Recliner" wrote:

I'm guessing that the 1992 stock has the highest power to weight
ratio of all LU trains. It's also the only stock to have every axle
motored. Do any other British trains (including main line) have
this?

I think it may have been the case with the old District Line R stock.
That always seemed to out-accelerate the 1962 stock at Mile End (but
maybe only from 0 - 5 mph).

Yes, I think the R Stock did have all axles powered, though I
suspect that the power to weight ratio of a train from 60 years ago
would have been less.

R stock had asymmetric bogies with only one of the two axles motored. I'm
pretty sure 92TS is the only stock with all axles motored.

--
Colin Rosenstiel

WHy is the central line so much faster?
 

In article , lid
(Michael Hoffman) wrote:

MIG wrote:
On Feb 11, 7:17 pm, Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison?

I guess it's to do with what's allowed with automatic operation.

The Victoria line is pretty fast too, for the same reason

For a different reason, I'd say. The Victoria Line doesn't follow the
lines of the streets above as much as earlier built tube lines so has a
higher maximum speed because it doesn't have the curvature.

92TS is the only tube stock on which every axle is motored, so probably
has better acceleration than other stocks.

--
Colin Rosenstiel

WHy is the central line so much faster?
 

Boltar wrote:
Had to go to a meeting at Hangar lane today. After white city the
train just took off, we must've been doing 40-50 mph. How come the
other tube lines are so slow in comparison? The piccadilly plods its
way to acton town and the northern line between east finchley and
finchley central seemed to barely get above 25mph the few times I did
it last year. Why is the central line different?

B2003
The signalling on many older lines was not set out for high speeds - even
Hammersmith to Acton Town was designed for "Flag Switch Down" running (no
weak field on the motors - normal for in tunnel lines) although my own
experience was that the notices were usually ignored! The Met main was
signalled for fast running (around 55 ISTR) with the fast road platforms and
junctions at Wembley Park designed for high speed through running as well as
catering for stopping trains.

The maximum runing speed of the Vic Line is around 50mph (47 mph headway, 55
mph trip IITC) - have no details of proposed upgrade.

The maximum running speed of the Central Line in the open air sections is
nominally 100 km/h (109 km/h trip speed) on 10 code. The resignalling had
to achieve a set target for potential round trip run time to ensure payment
of Governmental part of cost so the maximum speed possible was always used.

The restriction on the number of codes and spots available within the sytem
led to a "pseudo" 9 code to achieve 80 km/h on the tunnel stretches east of
Liverpool Street. The target was unattainable without this (8 code was ISTR
64 km/h) and we could only get this speed by a normal code by losing
performance elsewhere on the line at a greater run time penalty The basis
was a triple group of shortish track circuits (just long enough for a 10/8
brake) with the first two normally allowing 10/10 full speed runs but with
coasting applied. The third section was set for a 10/8 brake until the
train was close and proved to be below 80 whereupon the third section was
reset to 10/10. The coasting was switched off at a point which ensured that
the now accelerating train could not exceed the nominal 9 speed and coasting
was switched back on foer the next 3 track block.

In basic terms. The Central & Jubilee lines were the first to be equipped
with "modern" traction packages. The traditional traction packages
typically drew the maximum current just prior to changeover from series to
parallel. It was common to increase the maximum current at this point when
new stock replaced older with the linside section breakers having to be
reset to allow operation of the new stock, yet still protect the old from
short circuit. The introduction of the 1973 stock onto the Piccadilly was
fraught with difficulties if too many new trains ran in a section together!
The modern stock is usually set to draw a gradually increasing power to a
set maximum and then draw that current until maximum speed is attained.
This means that acceleration at speeds above 10 to 15 mph is considerably
enhanced on the modern stock.

--
Peter Corser
Leighton Buzzard, UK






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WHy is the central line so much faster?
 

On Mon, 11 Feb 2008 22:16:10 GMT, wrote:

And what about trains running fast on the Metropolitan Line? I heard that
the A62s could do close to 70 miles before they started to discover cracks
in the bogies.

Many years ago when I was just starting with LT I had a run out to
Amersham. On the way back I got a cab ride and certainly saw 70 mph on
the speedometer. It was a bit "shake, rattle and roll" as well but great
fun.
--
Paul C


Admits to working for London Underground!

WHy is the central line so much faster?
 

On 13 Feb, 15:05, "Peter Corser" wrote:
set maximum and then draw that current until maximum speed is attained.
This means that acceleration at speeds above 10 to 15 mph is considerably
enhanced on the modern stock.

Interesting post, thanks for that. Certainly on the central line the
acceleration is pretty impressive but I can't say I find the northern
or jubilee stocks anymore impressive performance wise than the stocks
they replaced. I used to live in finchley and travel on the northern
when the 59 & 72 stocks were still being used and they used to floor
it on the open air section from east finchley to finchley central no
doubt because its well over a mile of almost straight track. When
travelling on the 95 stock though it seemed all rather sedate. Perhaps
its just psychological because theres no screaming motor sounds and
the windows didn't sound like were about to fall out but even so , its
certainly nowhere near as quick as the 92 stock.

B2003

WHy is the central line so much faster?
 

Boltar wrote:
On 13 Feb, 15:05, "Peter Corser" wrote:
set maximum and then draw that current until maximum speed is
attained. This means that acceleration at speeds above 10 to 15 mph
is considerably enhanced on the modern stock.

Interesting post, thanks for that. Certainly on the central line the
acceleration is pretty impressive but I can't say I find the northern
or jubilee stocks anymore impressive performance wise than the stocks
they replaced. I used to live in finchley and travel on the northern
when the 59 & 72 stocks were still being used and they used to floor
it on the open air section from east finchley to finchley central no
doubt because its well over a mile of almost straight track. When
travelling on the 95 stock though it seemed all rather sedate. Perhaps
its just psychological because theres no screaming motor sounds and
the windows didn't sound like were about to fall out but even so , its
certainly nowhere near as quick as the 92 stock.

B2003
Boltae

The actual performance of modern stock is electronically controllable (a set
of EPROMS on the Central Line). If you are running mixed stock and/or the
signalling has not been updated the new stock has to match (or not better)
the old in performance terms if the overlaps are not to be compromised.

It may also be necessary to ensure that any regen is limited to ensure that
the performance of the old stock is not significantly improved.

Peter
--
Peter & Elizabeth Corser
Leighton Buzzard, UK


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WHy is the central line so much faster?
 

On 13 Feb, 22:57, "Peter Corser" wrote:
The actual performance of modern stock is electronically controllable (a set
of EPROMS on the Central Line). If you are running mixed stock and/or the
signalling has not been updated the new stock has to match (or not better)
the old in performance terms if the overlaps are not to be compromised.

But the old stock is long since gone to the depot in the sky. Surely
they could turn the wick up a bit on the new stocks by now? I can see
how the signalling would affect max line speed but I don't see why it
should limit the acceleration though.

B2003

WHy is the central line so much faster?
 

On Feb 14, 10:27*am, Boltar wrote:

But the old stock is long since gone to the depot in the sky. Surely
they could turn the wick up a bit on the new stocks by now?

Maybe they don't want an increase in their energy bill (and carbon
emissions) ? But I suspect a lot of this is simply to do with varying
track/bogie quality.
Tim

WHy is the central line so much faster?
 

Boltar wrote:
On 13 Feb, 22:57, "Peter Corser" wrote:
The actual performance of modern stock is electronically
controllable (a set of EPROMS on the Central Line). If you are
running mixed stock and/or the signalling has not been updated the
new stock has to match (or not better) the old in performance terms
if the overlaps are not to be compromised.

But the old stock is long since gone to the depot in the sky. Surely
they could turn the wick up a bit on the new stocks by now? I can see
how the signalling would affect max line speed but I don't see why it
should limit the acceleration though.

B2003
Boltar

I'm not sure what the current status of the signalling is, but with
"traditional" LUL signalling increasing the rate of acceleration of the
train without modifying the signalling (probably requires complete new
layout, in practice) can mean that the train can arrive at any intermediate
signal travelling significantly faster than the signalled overlap speed.
The potentially increased speed aproaching the next station could compromise
the safety of the home signal.

Conventional signals were laid out based upon the speed-distance curves
supplied by the Rolling Stock Engineer. Later (more recent) practices took
more account of worst case variations in performance and gradients. There
were even some blanket overlaps (nominally 100 km/h, although the practical
application included ISTR 97 km/h overlaps to physically fit the layout) on
the original Heathrow Extension west of Hounslow West.

Peter
--
Peter & Elizabeth Corser
Leighton Buzzard, UK


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