On Thu, 13 Aug 2009, David Cantrell wrote:

On Wed, Aug 12, 2009 at 12:35:45PM -0700, allanbonnetracy wrote:

Aren=92t the vast majority of car journeys less than three miles or
something like that?

For journeys of such short length, cycling is an entirely viable
alternative.

There's the small problem that while I can leave my car unattended on
the street it doesn't get stolen, because it's too heavy to lift and is
easily traceable, while if I were to leave a bike unattended on the
street, it would be. And there's nowhere else to leave it, because I,
like an awful lot of people, live in a small flat.

Have you heard of these things called "locks"?

Cycling is *not* a viable alternative for an awful lot of people.

I don't deny that. But for reasons of the distance of the commute, not the
problem of locking up.

tom

--
Jim-Jammity Jesus Krispy Kreme Christ on a ****-rocket!

In message op.uykf84moby8eno@sheepdog, at 21:23:18 on Wed, 12 Aug
2009, Colin McKenzie remarked:
A recent report says that it is worth spending up to £10,000 to turn
just one person into a regular cyclist.

A few years ago they spent about that much per cyclist [1] putting a
brand new shared cycle/foot path alongside one of the roads from
Cambridge to an adjoining village. Obviously, all the serious cyclists
refuse to use such a thing.

[1] That was predicted to use it per day.
--
Roland Perry

Tom Anderson wrote on 13 August 2009 18:32:19 ...
On Thu, 13 Aug 2009, Basil Jet wrote:

Bruce wrote:
On Thu, 13 Aug 2009 12:22:13 +0100, "Recliner"
wrote:
The ever-reliable Wiki source says that the 2009 stock is 2.68m wide
and the 1973 stock 2.629, so the 2009 stock is apparently 5cm or 2"
wider. It also says that, "Unlike the 1967 Tube Stock, the trains
are built 40 millimetres (1.6 in) wider to take advantage of the
Victoria line's slightly larger than normal loading gauge compared
to the other deep level tube lines."

Ironically, one of the reasons why the Victoria Line tunnel was built
to a larger diameter was to reduce air resistance. ;-)

It's not unreasonable to build the first stock for the line small to
reduce air resistance, and then build subsequent stock large to push the
hot air along.

If the air's hot, then building the train bigger means there's less of it
surrounding the train, so the train won't get heated up by it so much.

On the contrary, the bigger train has more surface area so is in contact
with a greater area of hot air. Also, the smaller gap between train and
tunnel will increase the frictional heating effect.

--
Richard J.
(to email me, swap 'uk' and 'yon' in address)

On Aug 13, 6:00*pm, 1506 wrote:
No, I meant it - I'd love to hear it...

This has the potential for Duhg levels of semantic shenanigans.

Be warned: Polson will drag you down to his level then beat you with
experience. *He is best ignored. *He won't go away, but you will not
be entrapped in an illogical discussion you can never win.

I've now agreed with AAH twice in a day. This can't be healthy.

--
John Band
john at johnband dot org
www.johnband.org

On Thu, 13 Aug 2009 22:51:17 GMT, "Richard J."
wrote:

Tom Anderson wrote on 13 August 2009 18:32:19 ...
On Thu, 13 Aug 2009, Basil Jet wrote:

Bruce wrote:
On Thu, 13 Aug 2009 12:22:13 +0100, "Recliner"
wrote:
The ever-reliable Wiki source says that the 2009 stock is 2.68m wide
and the 1973 stock 2.629, so the 2009 stock is apparently 5cm or 2"
wider. It also says that, "Unlike the 1967 Tube Stock, the trains
are built 40 millimetres (1.6 in) wider to take advantage of the
Victoria line's slightly larger than normal loading gauge compared
to the other deep level tube lines."

Ironically, one of the reasons why the Victoria Line tunnel was built
to a larger diameter was to reduce air resistance. ;-)

It's not unreasonable to build the first stock for the line small to
reduce air resistance, and then build subsequent stock large to push the
hot air along.

If the air's hot, then building the train bigger means there's less of it
surrounding the train, so the train won't get heated up by it so much.

On the contrary, the bigger train has more surface area so is in contact
with a greater area of hot air. Also, the smaller gap between train and
tunnel will increase the frictional heating effect.


The main heating effect comes partly from friction, but mainly from
turbulence. The smaller gap significantly increases the turbulence
and therefore the heating.

The increased turbulence is caused because the ratio of the cross
sectional area of the tunnel to the area of the annulus (the gap
between train and tunnel) is much higher than before, so the train
will force the same amount of air through a much smaller gap. The
result is higher flow velocities, which mean increased turbulence.

As I stated before, the Victoria Line tunnels were originally built to
a larger diameter in order to *reduce* air resistance. While the
trains were larger than previous Tube stock, they only used up a small
proportion of the increased cross sectional area of the tunnel
compared with previous Tube lines.

On 14 Aug, 01:49, Bruce wrote:
On Thu, 13 Aug 2009 22:51:17 GMT, "Richard J."





wrote:
Tom Anderson wrote on 13 August 2009 18:32:19 *....
On Thu, 13 Aug 2009, Basil Jet wrote:

Bruce wrote:
On Thu, 13 Aug 2009 12:22:13 +0100, "Recliner"
wrote:
The ever-reliable Wiki source says that the 2009 stock is 2.68m wide
and the 1973 stock 2.629, so the 2009 stock is apparently 5cm or 2"
wider. It also says that, "Unlike the 1967 Tube Stock, the trains
are built 40 millimetres (1.6 in) wider to take advantage of the
Victoria line's slightly larger than normal loading gauge compared
to the other deep level tube lines."

Ironically, one of the reasons why the Victoria Line tunnel was built
to a larger diameter was to reduce air resistance. *;-)

It's not unreasonable to build the first stock for the line small to
reduce air resistance, and then build subsequent stock large to push the
hot air along.

If the air's hot, then building the train bigger means there's less of it
surrounding the train, so the train won't get heated up by it so much.

On the contrary, the bigger train has more surface area so is in contact
with a greater area of hot air. Also, the smaller gap between train and
tunnel will increase the frictional heating effect.

The main heating effect comes partly from friction, but mainly from
turbulence. *The smaller gap significantly increases the turbulence
and therefore the heating.


But turbulence does not heat the air. Turbulent air generally stays at
the same temperature as the still air that was in position before.
Heat is all in the internal vibrations of the air molecules, not in
the bulk movement.
Heating still air will lead to turbulence (hot air rises), but
turbulence doesn't directly lead to heating; however for gases, the
frictional energy will be proportional to the velocity, so turbulence
will lead to greater friction and heating when the air interacts with
the tunnel / train.

The increased turbulence is caused because the ratio of the cross
sectional area of the tunnel to the area of the annulus (the gap
between train and tunnel) is much higher than before, so the train
will force the same amount of air through a much smaller gap. *The
result is higher flow velocities, which mean increased turbulence.

As I stated before, the Victoria Line tunnels were originally built to
a larger diameter in order to *reduce* air resistance. *While the
trains were larger than previous Tube stock, they only used up a small
proportion of the increased cross sectional area of the tunnel
compared with previous Tube lines.

On Fri, 14 Aug 2009 03:37:33 -0700 (PDT)
Andy wrote:
But turbulence does not heat the air. Turbulent air generally stays at

Any movement of one section of a fluid against another will heat it.
Eg if a propeller blows a load of air backwards that air will eventually
stop moving with respect the rest of the air mass around it. How do you
think the energy is lost? As heat of course.

B2003

On Thu, Aug 13, 2009 at 11:05:58AM +0000, Adrian wrote:
David Cantrell gurgled happily, sounding much like
they were saying:
And why can't these Londoners use the superb public transport in place
across the city, for an even bigger benefit?
We do, except that not all our journeys are in London or to places with
convenient public transport. Something like half the cars parked on my
road seem to be used only at weekends.
So Bruce's comments on provision of workplace recharging are irrelevant,

What about the other half that *are* used during the week. I presume
that quite a few of them are used to travel to/from work.

but the "one-shot" range is highly relevant.

Indeed. Cars are competitive with trains in terms of journey time for
short journeys of up to roughly 70 miles outside major cities. So at
minimum an electric car needs to be able to go 140 miles (for a return
journey), plus, say, another 20 miles just for a safe margin, at
current speeds without recharging. Otherwise people won't buy them.

Yes yes, I know, a train can cover 70 miles a lot faster than a car can.
But the car goes door to door so there's time taken to get to/from
stations at either end, and there's no waiting for the train either.

--
David Cantrell | Minister for Arbitrary Justice

[OS X] appeals to me as a monk, a user, a compiler-of-apps, a
sometime coder, and an easily amused primate with a penchant
for those that are pretty, colorful, and make nice noises.
-- Dan Birchall, in The Monastery

On Thu, Aug 13, 2009 at 06:30:18AM -0700, TimB wrote:
On Aug 13, 12:11 pm, David Cantrell wrote:
There's the small problem that while I can leave my car unattended on
the street it doesn't get stolen, because it's too heavy to lift and is
easily traceable, while if I were to leave a bike unattended on the
street, it would be. And there's nowhere else to leave it, because I,
like an awful lot of people, live in a small flat.
Cycling is *not* a viable alternative for an awful lot of people.
Well, you might hope for the odd car parking space to be removed and
replaced with stands for a dozen bikes. It happens occasionally....

They'd still get nicked.

A folder is also handy for carrying up to a flat.

No it isn't, and I've explained why before. Even folded they're still
quite big and get in the way. I have better uses for my limited space.
Also, I don't trust folding bikes to stay unfolded, and no bike is
reliable enough.

--
David Cantrell | http://www.cantrell.org.uk/david

NANOG makes me want to unplug everything and hide under the bed
-- brian d foy

On Thu, Aug 13, 2009 at 06:33:07PM +0100, Tom Anderson wrote:
On Thu, 13 Aug 2009, David Cantrell wrote:
There's the small problem that while I can leave my car unattended on
the street it doesn't get stolen, because it's too heavy to lift and is
easily traceable, while if I were to leave a bike unattended on the
street, it would be. And there's nowhere else to leave it, because I,
like an awful lot of people, live in a small flat.
Have you heard of these things called "locks"?

Funny man. Have you heard of these things called "bolt cutters"?

A lock is sufficient, I am sure, if the bike is left in a busy area
where a naughty fellow would be seen cutting the lock off. It is not
going to be sufficient at 4am on a Monday night on a residential street.

--
David Cantrell | semi-evolved ape-thing

[OS X] appeals to me as a monk, a user, a compiler-of-apps, a
sometime coder, and an easily amused primate with a penchant
for those that are pretty, colorful, and make nice noises.
-- Dan Birchall, in The Monastery