Peter Masson wrote:

Perhaps the Victoria Line needs to be extended into the open air, at
least so the piston effect of trains can add ventilation into the
tunnels, and ideally so that the next generation (49 stock) can have
aircon that takes heat out of the system and dumps it in the open
air. Take over Chingford from National Rail? Quadruple Northumberland
Park to Cheshunt, with a extended Victoria Line running the local
service?

A few years ago, a significant proportion of trains went to Northumberland
Park anyway - is that still true? I always wondered why - maybe it is to
cool the line.

On 24/7/09 21:55, in article , "Peter
Masson" wrote:



"D7666" wrote

There is a substantial uplift in heating effect from the new trains.
Unless my sums are seriously flawed, there'd have to be some seriously
hefty cooling gear to cool stations. Gear that itself draws power ...
maybe more than the entire train regenerated power is taken up by air-
con ?

Add to that the congestion relief works at Victoria and the more frequent
service, there'll be more passengers pumping kilowatts into the system.

Perhaps the Victoria Line needs to be extended into the open air, at least
so the piston effect of trains can add ventilation into the tunnels, and
ideally so that the next generation (49 stock) can have aircon that takes
heat out of the system and dumps it in the open air. Take over Chingford
from National Rail? Quadruple Northumberland Park to Cheshunt, with a
extended Victoria Line running the local service?

It was at one time intended to come to the surface beyond Hoe Street, as it
then was, and to terminate at Wood Street, with platforms alongside the BR
ones. I don't know when this was dropped from the plans.

On Jul 24, 10:15*pm, Andy wrote:

"In order to make use of the additional throughput capability of the
new signalling, the
2009 Stock has a higher performance than the current stock. The
existing 1967
Tube Stock draws about 2,700 amps maximum, while the 2009 Tube Stock
will draw
3,500 and is capable of drawing up to 4,500 amps."

This looks like well under double the peak current draw.


You've missed the whole point.

Its not the PEAK current thats the issue. This has been explained in
uk.railway several times before - and it seems to be a fundamental
issue that headline writers can't get right.

With DC motors the PEAK current is very large but drops off very
quickly and gets ever smaller as the train accelerates.

With AC motors it is a constant current, its not as high as the DC
peak, but it never tapers off, it is flat, across the whole train
speed. But at all times it is considerably higher than the DC motor
train at speed.

3500 A constant is much much more heating effect than 2700 A that
drops off rapidly. Thats how AC asynchronous and DC commutator motors
work, full stop.

It all amounts to much much more I^2*R heat to get rid of when trains
are motoring than from a DC motor train.


--
Nick

On Fri, 24 Jul 2009 14:57:26 -0700 (PDT), D7666
wrote:

With AC motors it is a constant current, its not as high as the DC
peak, but it never tapers off, it is flat, across the whole train
speed. But at all times it is considerably higher than the DC motor
train at speed.

Although there is also the issue of DC versus RMS current. When they
developed the cross-channel cables that transfer electricity between
..uk and .fr they made a schoolboy error and forgot they were
transferring DC, with results that as far as I can tell only
electrical engineers find actually amusing.

Guy
--
http://www.chapmancentral.co.uk

On Jul 24, 11:00*pm, "Just zis Guy, you know?"
wrote:

With AC motors it is a constant current, its not as high as the DC
peak, but it never tapers off, it is flat, across the whole train
speed. But at all times it is considerably higher than the DC motor
train at speed.

Although there is also the issue of DC versus RMS current. *


Yes ...

that can be a source of confusion

..... but we are talking here of the current draw on the DC traction
third rail in both cases i.e. for both the DC motor [1967] and AC
motor [2009] trains. RMS does not come into this debate in the
discussion as it is a tthe moment.


--
Nick

In article ,
(Charles Ellson) wrote:

On Thu, 23 Jul 2009 11:19:39 +0100, "Recliner"
wrote:

"Peter Masson" wrote in message

"Recliner" wrote

Surely there were large numbers of 1959 and 1962 stock trains in
service by then? Admittedly, their design was pretty similar to the
1938s, so they may not have seen much newer.
They did, and the 1959 stock were the first 'silver' trains - but
they did not run on the lines used by the previous poster at the
time.

Weren't there silver R stock trains before then?

1949 IIRC - apparently they dismantled one after they were withdrawn
and the body was reckoned to still have a few more years left in it.

Unlike the 1959 & 1962 TS which had steel underframes, the R49 (and R59)
stock was all-aluminium. 6 DMs were included in the R49 stock which
otherwise ran with steel R38 converted DMs, allowing the formation of two
all-aluminium 8 car trains. One train was left unpainted from its
introduction in 1953. The first "silver" tube stock was the three 1956
prototype trains introduced on the Piccadilly Line, precursors of the 1959
TS.

I have a picture of the unique West-end unpainted R49 DM at Earls Court on
my web site. See www.rosenstiel.co.uk/trains.

--
Colin Rosenstiel

On Jul 24, 10:57*pm, D7666 wrote:
On Jul 24, 10:15*pm, Andy wrote:

"In order to make use of the additional throughput capability of the
new signalling, the
2009 Stock has a higher performance than the current stock. The
existing 1967
Tube Stock draws about 2,700 amps maximum, while the 2009 Tube Stock
will draw
3,500 and is capable of drawing up to 4,500 amps."

This looks like well under double the peak current draw.

You've missed the whole point.


No I've not, you've missed mine. You were the one mentioning 3 times
the current draw, when the numbers say less than twice the current
draw.

Its not the PEAK current thats the issue. This has been explained in
uk.railway several times before - and it seems to be a fundamental
issue that headline writers can't get right.

With DC motors the PEAK current is very large but drops off very
quickly and gets ever smaller as the train accelerates.

With AC motors it is a constant current, its not as high as the DC
peak, but it never tapers off, it is flat, across the whole train
speed. But at all times it is considerably higher than the DC motor
train at speed.

3500 A constant is much much more heating effect than 2700 A that
drops off rapidly. Thats how AC asynchronous and DC commutator motors
work, full stop.


But only constant current whilst the train is actually motoring, it
would be a very strange train which was drawing 3500A when stationary
or decelerating. I understand the workings of the different sorts of
motors, I was just trying to point out that your estimates seemed to
be in error.

It all amounts to much much more I^2*R heat to get rid of when trains
are motoring than from a DC motor train.


Yes and as the current is being drawn much more consistently, a large
proportion of the regained energy from the regeneration will be going
into powering other trains, rather than heating braking resistors as
it does at present. The current 1967 stock braking system will be
dumping a lot of heat straight into the stations, with 2009 stock
regeneration, a lot of that energy will instead be used.

On Jul 24, 11:44*pm, Andy wrote:

No I've not, you've missed mine. You were the one mentioning 3 times
the current draw, when the numbers say less than twice the current
draw.



If the cont power rating of 2009 stock is 1800 kW and the cont power
rating of 1967 sock is 848 kW and they are both drawing that power at
630 V DC then that alone, comparing one 8-car train with another draws
2.12 times as much current from traction DC.

Or are you going to tell me now that the Laws of Ohm, Kirchoff,
Newton, and anyone else with an established theorem of electricity or
mechanics is wrong ?

If not then read on.

Making no changes to the service, across the whole line, its must then
follow as 2.12 times as much current.

But there are 37 trains (I think) in the present timetable. That [I
think] goes to 41 with full 2009 stock service post VUl. That actually
up ~10%. So its 2.33 times the current.

Thats the base load, on cont ratings, before we even look at one hour
or short term overloads.

Those new trains in the full timetable will work harder - instead of
[?] 28 TPH they work 33[??] TPH - so they will be pushed harder with
the new ATO than the old ATO does with 1967 stock. (You only have to
go on the Central Line to see how a more modern ATO system pushes
trains - and that is a system that is very like the one going in on
VUL, just a refined version of it.)

But only constant current whilst the train is actually motoring,

In the same way the 1967 stock don't draw current all the time only
when motoring.

The *relative* load proportion of 1967 and 2009 stock at continuous
rating thus remains at around 2.33 times.

So far I've only looked at traction motor load.

Add air con etc - anyone want to esitimate or state what the aircon
load of 2009 stock is ?

It is around 1 MW on a Eurostar. I'm not seriously suggesting 2009
stock is the same load, but write it as its the only one I know off
the top of my head to show how siginificant these loads are.


That traction load goes on top the 2.33 ... in round figures with
auxiliary load we approach 3x.

--
Nick

D7666 wrote:

If the cont power rating of 2009 stock is 1800 kW and the cont power
rating of 1967 sock is 848 kW and they are both drawing that power at
630 V DC then that alone, comparing one 8-car train with another draws
2.12 times as much current from traction DC.

Or are you going to tell me now that the Laws of Ohm, Kirchoff,
Newton, and anyone else with an established theorem of electricity or
mechanics is wrong ?

If not then read on.

Making no changes to the service, across the whole line, its must then
follow as 2.12 times as much current.

But there are 37 trains (I think) in the present timetable. That [I
think] goes to 41 with full 2009 stock service post VUl. That actually
up ~10%. So its 2.33 times the current.

Thats the base load, on cont ratings, before we even look at one hour
or short term overloads.

Those new trains in the full timetable will work harder - instead of
[?] 28 TPH they work 33[??] TPH - so they will be pushed harder with
the new ATO than the old ATO does with 1967 stock. (You only have to
go on the Central Line to see how a more modern ATO system pushes
trains - and that is a system that is very like the one going in on
VUL, just a refined version of it.)

But only constant current whilst the train is actually motoring,

In the same way the 1967 stock don't draw current all the time only
when motoring.

The *relative* load proportion of 1967 and 2009 stock at continuous
rating thus remains at around 2.33 times.

So far I've only looked at traction motor load.

Add air con etc - anyone want to esitimate or state what the aircon
load of 2009 stock is ?

It is around 1 MW on a Eurostar. I'm not seriously suggesting 2009
stock is the same load, but write it as its the only one I know off
the top of my head to show how siginificant these loads are.

That traction load goes on top the 2.33 ... in round figures with
auxiliary load we approach 3x.

I suspect the aircon would only be on when the trains were regeneratively
braking, or when a significant chunk of the fleet was stationary in the
tunnel and drawing no motor power - possibly also when the trains were
coasting, but I see no need to have the aircon working when the trains are
accelerating.

On Jul 25, 12:14*am, D7666 wrote:
On Jul 24, 11:44*pm, Andy wrote:

No I've not, you've missed mine. You were the one mentioning 3 times
the current draw, when the numbers say less than twice the current
draw.

If the cont power rating of 2009 stock is 1800 kW and the cont power
rating of 1967 sock is 848 kW and they are both drawing that power at
630 V DC then that alone, comparing one 8-car train with another draws
2.12 times as much current from traction DC.

Or are you going to tell me now that the Laws of Ohm, Kirchoff,
Newton, and anyone else with an established theorem of electricity or
mechanics is wrong ?


Stop being so condescending.

If not then read on.

Making no changes to the service, across the whole line, its must then
follow as *2.12 times as much current.

But there are 37 trains (I think) in the present timetable. That [I
think] goes to 41 with full 2009 stock service post VUl. That actually
up ~10%. So its 2.33 times the current.

Thats the base load, on cont ratings, before we even look at one hour
or short term overloads.

Those new trains in the full timetable will work harder - instead of
[?] 28 TPH they work 33[??] TPH - so they will be pushed harder with
the new ATO than the old ATO does with 1967 stock. (You only have to
go on the Central Line to see how a more modern ATO system pushes
trains - and that is *a system that is very like the one going in on
VUL, just a refined version of it.)

But only constant current whilst the train is actually motoring,

In the same way the 1967 stock don't draw current all the time only
when motoring.

The *relative* load proportion of 1967 and 2009 stock at continuous
rating thus remains at around 2.33 times.

So far I've only looked at traction motor load.

Add air con etc - anyone want to esitimate or state what the aircon
load of 2009 stock is ?

What Aircon? 2009 stock isn't fitted although the S Stock will be. The
original point of the discussion was why it hasn't got the aircon.


It is around 1 MW on a Eurostar. I'm not seriously suggesting 2009
stock is the same load, but write it as its the only one I know off
the top of my head to show how siginificant these loads are.

That traction load goes on top the 2.33 ... in round figures with
auxiliary load we approach 3x.


Ok, another question, since you seem to be disregarding my attempts to
point you towards the energy saving of the regeneration. Why are you
assuming that R is constant when the modern AC motors and their
control systems are considerably more efficient than the DC systems
being replaced. A more powerful modern traction system doesn't
necessarily generate twice as much heat just because it has twice as
much power at its disposal.