"Andy" wrote

The current used by the system is NOT the amount of waste heat
generated by the train. You keep mentioning the power consumption, but
this has nothing directly to do with the amount of waste heat
generated by the trains (for a given design it will be related of
course, but not between designs). I have never said that the trains
will be consuming less power, just trying to point out that the power
will be used much more efficiently in a modern electrical system than
it was in a 1960s design.

The electrical energy introduced into the system does end up as heat. It
might on the way be used to accelerate the train, converting electrical
energy into kinetic energy, but this will all end up as heat, whether
through friction or braking. If regenerative braking puts electrical energy
back into the system, this reduces the electrical energy introduced into the
system.

Essentially all the electrical energy ends up as heat, and has to be removed
from the system through ventilation. You can't break the First Law (of
Thermodynamics).

Peter

On Jul 26, 5:58*pm, "Peter Masson" wrote:
"Andy" wrote



The current used by the system is NOT the amount of waste heat
generated by the train. You keep mentioning the power consumption, but
this has nothing directly to do with the amount of waste heat
generated by the trains (for a given design it will be related of
course, but not between designs). I have never said that the trains
will be consuming less power, just trying to point out that the power
will be used much more efficiently in a modern electrical system than
it was in a 1960s design.

The electrical energy introduced into the system does end up as heat. It
might on the way be used to accelerate the train, converting electrical
energy into kinetic energy, but this will all end up as heat, whether
through friction or braking. If regenerative braking puts electrical energy
back into the system, this reduces the electrical energy introduced into the
system.

Essentially all the electrical energy ends up as heat, and has to be removed
from the system through ventilation. You can't break the First Law (of
Thermodynamics).


I don't disagree. But as you say, it is the whole system, not just one
train. A much smaller percentage of the electrical energy that the
train itself uses, with regeneration, is going to end up as heat than
with rheostatic braking. The heat that is produced will be more spread
out as well. With rheostatic braking, the resistor bank is a
concentrated 'hot spot'. Much of the remaining kinetic energy will go
into movements of the air and so heat will get deposited in other
parts of the stations than the platforms (as well as going into
ventilation shafts). Just think of the breeze that can be felt for
quite a way (including up the escalator shafts) when a train arrives
into a platform. Heat energy is the internal vibrations of molecules
(both in the air and surroundings in a station), whilst the breeze /
bulk motion of the air is still kinetic energy.

In addition, some kinetic energy will be converted to potential energy
when stopping at stations with a hump (uphill into platform, downhill
out of platform). The potential energy works better for the lines that
go above ground, of course, as the kinetic energy underground becomes
potential energy when the train surfaces.

On Sun, 26 Jul 2009 10:37:55 -0700 (PDT), Andy wrote:

In addition, some kinetic energy will be converted to potential energy
when stopping at stations with a hump (uphill into platform, downhill
out of platform).

I'm aware that the core part of the Central Line has these humps -
does the Vic? Which other tube lines have them?

On Jul 26, 6:54*pm, asdf wrote:
On Sun, 26 Jul 2009 10:37:55 -0700 (PDT), Andy wrote:
In addition, some kinetic energy will be converted to potential energy
when stopping at stations with a hump (uphill into platform, downhill
out of platform).

I'm aware that the core part of the Central Line has these humps -
does the Vic? Which other tube lines have them?

The Victoria line is not so well endowed with them, due to the
complexities of fitting the tunnels around the existing
infrastructure, but there are still some. Stratford on the Central
line is a lovely example of the hump!!

"Andy" wrote in message

On Jul 26, 6:54 pm, asdf wrote:
On Sun, 26 Jul 2009 10:37:55 -0700 (PDT), Andy wrote:
In addition, some kinetic energy will be converted to potential
energy when stopping at stations with a hump (uphill into platform,
downhill out of platform).

I'm aware that the core part of the Central Line has these humps -
does the Vic? Which other tube lines have them?

The Victoria line is not so well endowed with them, due to the
complexities of fitting the tunnels around the existing
infrastructure, but there are still some. Stratford on the Central
line is a lovely example of the hump!!

Mile End, too, I imagine.

In message , Tony Dragon
writes
God, your making me feel my age, I can remember the 'Q' stock on the
District,
So can I. I can also remember tube stock where the first half of the
driving car was taken up with equipment which went under floor in 38
stock, but I can't remember what they were called.
--
Clive

On 28 July, 15:06, Clive wrote:
In message , Tony Dragon
writesGod, your making me feel my age, I can remember the 'Q' stock on the
District,

So can I. * I can also remember tube stock where the first half of the
driving car was taken up with equipment which went under floor in 38
stock, but I can't remember what they were called.

Usually called Standard Stock, although they were anything but
standard, being build from 1923 - 1934 with many detail differences!!
Sometimes referred also referred to as 1923 Stock.

On Tue, 28 Jul 2009 15:06:15 +0100, Clive
wrote:

In message , Tony Dragon
writes
God, your making me feel my age, I can remember the 'Q' stock on the
District,
So can I. I can also remember tube stock where the first half of the
driving car was taken up with equipment which went under floor in 38
stock, but I can't remember what they were called.

Standard stock.In various batches from 1923 onwards, known by the
year. Organised as a single fleet because they were compatible with
each other. Hence "Standard".

Apart from the equipment taking up space in the motor cars they were
distinctive because of their low clerestory roofs with scoop
ventilators.

The first electric stock on the Isle of White was fromrd of these,
called 4-VEC and 3-TIS units.

http://www.semgonline.com/gallery/class485_486_01.html

On Tue, 28 Jul 2009 15:06:15 +0100, Clive
wrote:
In message , Tony Dragon
writes
God, your making me feel my age, I can remember the 'Q' stock on the
District,
So can I. I can also remember tube stock where the first half of the
driving car was taken up with equipment which went under floor in 38
stock, but I can't remember what they were called.


The most recent of them were called "Standard stock".

"Christopher A. Lee" wrote in message

On Tue, 28 Jul 2009 15:06:15 +0100, Clive
wrote:

In message , Tony Dragon
writes
God, your making me feel my age, I can remember the 'Q' stock on the
District,
So can I. I can also remember tube stock where the first half of
the driving car was taken up with equipment which went under floor
in 38 stock, but I can't remember what they were called.

Standard stock.In various batches from 1923 onwards, known by the
year. Organised as a single fleet because they were compatible with
each other. Hence "Standard".

Apart from the equipment taking up space in the motor cars they were
distinctive because of their low clerestory roofs with scoop
ventilators.

The first electric stock on the Isle of White was fromrd of these,
called 4-VEC and 3-TIS units.

.... some of which can be seen (occasionally) in the Acton Museum Depot