"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?

"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

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).

"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.

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

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

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

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

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

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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