Doctor Drivel wrote:

A scab is a SCAB.

SCAB=?
South Coast Air Basin?
Svenska Cellulosa Aktiebolaget?
Southern California American Sportbikes?
Side-Channel Atomic Block?
Special Combat Aviation Battalion?
South Charleston Adjustment Bureau, Inc.?

--
Tciao for Now!

John.

"John Williamson" wrote in message
...
Doctor Drivel wrote:

A scab is a SCAB.

SCAB=?

A scab is a SCAB.

On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...

Andy

Doctor Drivel wrote:

"John Williamson" wrote in message
...
Doctor Drivel wrote:

A scab is a SCAB.

SCAB=?

A scab is a SCAB.

A covering made by the body over a cut which promotes healing?

--
Tciao for Now!

John.

"John Williamson" wrote in message
...
Doctor Drivel wrote:

"John Williamson" wrote in message
...
Doctor Drivel wrote:

A scab is a SCAB.

SCAB=?

A scab is a SCAB.

A

A scab is a SCAB. No doubt you are one.

Doctor Drivel wrote:

"John Williamson" wrote in message
...
Doctor Drivel wrote:

"John Williamson" wrote in message
...
Doctor Drivel wrote:

A scab is a SCAB.

SCAB=?

A scab is a SCAB.

A

A scab is a SCAB. No doubt you are one.

Looks Nope, no scabs round here. Then again, I've not cut myself
lately, and I don't owe anyone in California any money.

I live in hope that one day, you will start to make some form of sense.

Otherwise, my theory that you are a poorly programmed chatbot is gaining
credence by the hour.

--
Tciao for Now!

John.

"John Williamson" wrote in message
...
Doctor Drivel wrote:

"John Williamson" wrote in message
...
Doctor Drivel wrote:

"John Williamson" wrote in message
...
Doctor Drivel wrote:

A scab is a SCAB.

SCAB=?

A scab is a SCAB.

A

A scab is a SCAB. No doubt you are one.

Looks

A scab is a SCAB.

"charles" wrote in message
...
In article m,
dennis@home wrote:


"The Natural Philosopher" wrote in message
...

tunnelling by definition means that you are going deep enough to make
cut and cover impractical

So how deep is that? 20 feet? 50 feet?

Its very hard to cut and cover under main roads, railways, etc. so they
frequently put in a shallow tunnel.

There are plenty of situations on the M25 where existing roads and
railways
have been put onto bridges. This would work for railways, too.

Not quite a tunnel running underneath a main road to avoid going under the
buildings either side though.

Its relatively easy to dig a couple of big holes either side of a railway
and then build a bridge under it.

"Derek Geldard" wrote in message
...
On Sat, 31 Dec 2011 19:38:40 +0000, Ghostrecon wrote:

There is data in the current financial figures to show this is indeed
happening.

facts, however true (or false) will never convince those if it doesnt fit
their preconceptions :-)

That's true (or false). :-))

Whatever ...

What has Gordon mac ****e-Features done with my pension ?

I hope he has spent it on wine, women and song.

"Tim Streater" wrote in message
...
In article , Doctor Drivel wrote:

"Tim Streater" wrote in message
...
In article , Doctor Drivel
wrote:

A scab is a SCAB.

So tell us, drivel,

A scab is a SCAB.

Avoiding

A scab is a SCAB.

"Andy Champ" wrote in message
. uk...
On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

I know.


But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...

We know that too.

Doctor Drivel wrote:

A scab is a SCAB.

And a duck is a DUCK. Most of which make more sense than you.

--
Tciao for Now!

John.

In article ,
lid says...

On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...


Isn't that how this argument started ...?

--

Terry

Doctor Drivel wrote:

"Tim Streater" wrote in message
...
In article , Doctor Drivel
wrote:

"Tim Streater" wrote in message
...
In article , Doctor Drivel
wrote:

A scab is a SCAB.

So tell us, drivel,

A scab is a SCAB.

Avoiding

A scab is a SCAB.

Oh, gawd, the needle's stuck.
Taps side of computer

Let's see if that fixes it.

--
Tciao for Now!

John.

"Terry Casey" wrote in message
...
In article ,
lid says...

On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...


Isn't that how this argument started ...?

No. It started when I said a single large tunnel is cheaper than two small
ones.
Cheaper may not mean better it depends on the requirements.

On Mon, 02 Jan 2012 18:57:23 +0000, Derek Geldard
wrote:

What has Gordon mac ****e-Features done with my pension ?

Perhaps he snipped it.

Andy Champ wrote:
On 31/12/2011 08:34, harry wrote:
On Dec 30, 9:10 pm, Andy wrote:
On 30/12/2011 07:58, harry wrote:

On Dec 29, 4:48 pm, wrote:
On Thu, 29 Dec 2011 01:33:17 -0800 (PST),
wrote:

The weight of the on board capacitors would in itself be an energy
store (kinetic energy).

And how do they get up to speed - magic pixie beans?

Stupid boy. You don't get anything for nothing.
But storing kinetic energy is far more efficient than charging/
discharging batteries.

Kinetic energy stored as vehicle momentum is of no use for accelerating
the vehicle. At the time you need it it isn't there.

It's also of no use for climbing hills - the extra weight exactly
cancels out the extra KE.

In fact I can't think of a use for extra mass at all. Except in a road
roller.

Andy

But it can be used for charging batteries. Which is exactly what
happens in electric cars. In ICE cars, it is lost.
Bad news during cornering though.

Harry,

Lets take two examples, a 1000kg car and a 2000kg one. We'll give them
identical power trains.

Accelerate them to 10m/s (22mph, a traffic sort of speed) will take:

1/2 * 1000 * 10 * 10 = 50 kJ for the 1000Kg car
100kJ for the 2000Kg one.
Lighter is better.

We'll go along the road a bit. Air drag is the same, rolling resistance
slightly higher for the heavier one.
Lighter is better.

Come to a stop. Perhaps the recharge cycle is 80% efficient, so we get
back 40kJ for the lighter car, 80 for the heavy one.
The loss for the start-stop cycle is less for the lighter car.

As I say I can think of no case where heavy is better.

Andy

The only use weight has in a car is to make it easier to give a smooth ride.

The ratio of sprung to unsprung weight is at some level a measure of the
smoothness of the ride.

Andy Champ wrote:
On 31/12/2011 11:26, The Natural Philosopher wrote:

I don't know where you've been, but lots of conventional IC engined cars
now use their alternator to store energy when slowing.

No they dont.

BMW call it "Efficient Dynamics". I suspect it makes F-all difference
though - just takes a little load off the engine while under load,
rather than storing it to accelerate with.

yep. the dynamo and and water pump used to take about 30% of the car
engine's power before the days of alternators electric fans and so on.

Now its the power steering pump and the air con instead :-)

Andy

harry wrote:
On Jan 2, 6:07 pm, Andy Champ wrote:
On 31/12/2011 11:26, The Natural Philosopher wrote:



I don't know where you've been, but lots of conventional IC engined cars
now use their alternator to store energy when slowing.
No they dont.
BMW call it "Efficient Dynamics". I suspect it makes F-all difference
though - just takes a little load off the engine while under load,
rather than storing it to accelerate with.

Andy

Well they would have to have somewhere to store this energy.

I seem to remember that BMW were working on an ICE that had few
mechanical parts, every thing was electric. Water pump, oil pump,
valves, cooling fan, steering, AC, fuel injection. They were using
heat from the exhaust with a thermopile to charge the battery,
therefore no alternator.
There was only a crankshaft, con rods valves and pistons. No camshaft.

Dunno what became of it.

the realised like all renewable energy it was an expensive piece of
****e, probably.

Andy Champ wrote:
On 31/12/2011 16:14, dennis@home wrote:

Extra mass in vehicles is never a good idea.
You need the lowest mass that will provide a safe environment for the
passengers and that is it.

Extra mass doesn't help when going up and down hills unless you think
doing 1 mph on the level and rolling down a hill up to 70(or whatever
the speed limit is) and then slowing down to 1 mph as you go up the
other side is actually useful. Driving at the speed limit means there is
nowhere to store any extra kinetic energy without speeding up which is
probably both illegal and dangerous.

Interesting thought that safety dictates you should _slow_ on the
_downhill_ because the braking distance increases...


and don't I know it..one of the horridest experiences locked wheels on a
wet road going down..and a stopped car at the bottom...

JUST managed to steer cadence brake and somehow get the car stopped.
With a few feet to spare.
Andy

Tim Streater wrote:
In article
,
harry wrote:

On Jan 2, 6:07 pm, Andy Champ wrote:
On 31/12/2011 11:26, The Natural Philosopher wrote:

I don't know where you've been, but lots of conventional IC
engined cars
now use their alternator to store energy when slowing.

No they dont.

BMW call it "Efficient Dynamics". I suspect it makes F-all difference
though - just takes a little load off the engine while under load,
rather than storing it to accelerate with.

Andy

Well they would have to have somewhere to store this energy.

I seem to remember that BMW were working on an ICE that had few
mechanical parts, every thing was electric. Water pump, oil pump,
valves, cooling fan, steering, AC, fuel injection. They were using
heat from the exhaust with a thermopile to charge the battery,
therefore no alternator.
There was only a crankshaft, con rods valves and pistons. No camshaft.

Dunno what became of it.

I expect they turned the engine over once and broke the valve stems.
Then the BMW engineers turned to each other and said "Oh! *That's* what
the camshaft is for!".


:-)

The fact is mechanical drives use less power than electric ones by and
large.

And its usually easier to declutch something you dont need than simply
take the load off the alternator.

dennis@home wrote:


"Terry Casey" wrote in message
...
In article ,
lid says...

On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...


Isn't that how this argument started ...?

No. It started when I said a single large tunnel is cheaper than two
small ones.

And we are coming to realise it may very well not be.

But then its usual to find that whatever you say, the converse is true.

Rather like listening to a Labour party person.

Cheaper may not mean better it depends on the requirements.

Well, a comma is cheap, and would have made your inane truism at least
grammatically correct.

"The Natural Philosopher" wrote in message
...
dennis@home wrote:


"Terry Casey" wrote in message
...
In article ,
lid says...

On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...


Isn't that how this argument started ...?

No. It started when I said a single large tunnel is cheaper than two
small ones.

And we are coming to realise it may very well not be.

But then its usual to find that whatever you say, the converse is true.

Well so far there has been no evidence of what you say.


Rather like listening to a Labour party person.

In your case yes, is your alter ego going to say "a scab is a SCAB"?


Cheaper may not mean better it depends on the requirements.

Well, a comma is cheap, and would have made your inane truism at least
grammatically correct.

Here's one, for you to use.

On Mon, 02 Jan 2012 20:39:44 -0000, dennis@home
wrote:



"Terry Casey" wrote in message
...
In article ,
lid says...

On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...


Isn't that how this argument started ...?

No. It started when I said a single large tunnel is cheaper than two
small ones.
Cheaper may not mean better it depends on the requirements.

And no-one has yet pointed out the obvious issue of the geology which
might overwhelm the other issues.

--
Rod

In article ,
polygonum wrote:
On Mon, 02 Jan 2012 20:39:44 -0000, dennis@home
wrote:



"Terry Casey" wrote in message
...
In article ,
lid says...

On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...


Isn't that how this argument started ...?

No. It started when I said a single large tunnel is cheaper than two
small ones.
Cheaper may not mean better it depends on the requirements.

And no-one has yet pointed out the obvious issue of the geology which
might overwhelm the other issues.

Indeed so.. the London underground is in "London clay" and the Chunnel was
in Chalk. A bit different if the ground is granite.

--
From KT24

Using a RISC OS computer running v5.16

"polygonum" wrote in message
news
On Mon, 02 Jan 2012 20:39:44 -0000, dennis@home
wrote:



"Terry Casey" wrote in message
...
In article ,
lid says...

On 01/01/2012 18:30, dennis@home wrote:
Its cheaper to bore one tunnel these days.

It's always been cheaper.

But two tunnels gives you an escape route via cross passages. It help
prevent collisions. It takes away the drag from passing trains.

And BTW you can profile them differently for acceleration...


Isn't that how this argument started ...?

No. It started when I said a single large tunnel is cheaper than two
small ones.
Cheaper may not mean better it depends on the requirements.

And no-one has yet pointed out the obvious issue of the geology which
might overwhelm the other issues.

Geology is covered by requirements about which I have stated on several
replies.

In message , John Williamson
writes
Doctor Drivel wrote:
"Tim Streater" wrote in message
...
In article , Doctor Drivel
wrote:

"Tim Streater" wrote in message
...
In article , Doctor
Drivel wrote:

A scab is a SCAB.

So tell us, drivel,

A scab is a SCAB.

Avoiding
A scab is a SCAB.

Oh, gawd, the needle's stuck.
Taps side of computer

Let's see if that fixes it.


The use of the word tap in the same post as drivel usually ends in a
flood


--
geoff

Huge wrote:
On 2012-01-02, Andy Champ wrote:
On 31/12/2011 08:34, harry wrote:
On Dec 30, 9:10 pm, Andy wrote:
On 30/12/2011 07:58, harry wrote:

On Dec 29, 4:48 pm, wrote:
On Thu, 29 Dec 2011 01:33:17 -0800 (PST),
wrote:
The weight of the on board capacitors would in itself be an energy
store (kinetic energy).
And how do they get up to speed - magic pixie beans?
Stupid boy. You don't get anything for nothing.
But storing kinetic energy is far more efficient than charging/
discharging batteries.
Kinetic energy stored as vehicle momentum is of no use for accelerating
the vehicle. At the time you need it it isn't there.

It's also of no use for climbing hills - the extra weight exactly
cancels out the extra KE.

In fact I can't think of a use for extra mass at all. Except in a road
roller.

Andy
But it can be used for charging batteries. Which is exactly what
happens in electric cars. In ICE cars, it is lost.
Bad news during cornering though.
Harry,

Lets take two examples, a 1000kg car and a 2000kg one. We'll give them
identical power trains.

Accelerate them to 10m/s (22mph, a traffic sort of speed) will take:

1/2 * 1000 * 10 * 10 = 50 kJ for the 1000Kg car
100kJ for the 2000Kg one.
Lighter is better.

We'll go along the road a bit. Air drag is the same, rolling resistance
slightly higher for the heavier one.
Lighter is better.

Come to a stop. Perhaps the recharge cycle is 80% efficient, so we get
back 40kJ for the lighter car, 80 for the heavy one.
The loss for the start-stop cycle is less for the lighter car.

As I say I can think of no case where heavy is better.

Armoured cars.


No, even there weight per se is no advantage, unless you want not to be
blown into the air.
But even that is arguable.

armour is not about weight, its about energy absorption.


They are not always connected. As anyone who has fired a 22 round into
a steel plate, and a straw bale will tell you. The straw bale wins
weight for weight.

"geoff" wrote in message
...

The use of the word tap in the same post as drivel usually ends in a flood

Fantastic Maxie. What a quip. What a quip! Are you getting over New Year
Maxie? Maxie you are an outstanding person indeed. Fantastic, you are even
in a Paddy band. What a Man! Playing in the Paddy band must be wonderful
at Christmas and New Year. Maxie, when you dance on stage with your turned
down wellies and donkey jacket you must look the part. Such sartorial
elegance indeed - so you. Maxie, when you dance on stage with your turned
down wellies and donkey jacket, no doubt you own that stage. Yes Maxie, you
own that stage. And with you hair-tingling version of Danny Boy throwing
your arms back at full voice, it must be an amazing sight and sound. You
make that song your own. Yes Maxie, you make that song your own.

Fantastic.

On 23/12/11 14:43, Dave Plowman (News) wrote:
In ,
wrote:
In the Toyota system, even at high speed it's possible to be
running on electric power alone

Thus draining the battery which has to be re-charged. Both quite
inefficient processes.


The battery can charge while the petrol engine is running - the engine will
run at an RPM suitable for maximum efficiency, not just enough RPM to drive
the wheels. "Spare" power at this RPM goes into recharging the battery

On 26/12/11 11:31, Doctor Drivel wrote:

"Dave Plowman (News)" wrote in message
...

It's common to give the very best MPG that can be achieved under ideal
conditions.

The Mk 3 Pirus get 75mpg in average driving. This is hard for senile fools to
comprehend.

No, it doesn't.

But it will get about 50mpg without trying and 60mpg if you try hard. If you
do a lot of stop-start town driving you'll get significantly more.

"funkyoldcortina" wrote in message
...
On 23/12/11 14:43, Dave Plowman (News) wrote:
In ,
wrote:

In the Toyota system, even at high speed it's possible to be
running on electric power alone

Thus draining the battery which has to be re-charged. Both quite
inefficient processes.

The battery can charge while the petrol engine is running - the engine
will run at an RPM suitable for maximum efficiency, not just enough RPM to
drive the wheels. "Spare" power at this RPM goes into recharging the
battery

Yep.

"funkyoldcortina" wrote in message
...
On 26/12/11 11:31, Doctor Drivel wrote:

"Dave Plowman (News)" wrote in message
...

It's common to give the very best MPG that can be achieved under ideal
conditions.

The Mk 3 Pirus get 75mpg in average driving. This is hard for senile
fools to
comprehend.

No, it doesn't.

But it will get about 50mpg without trying and 60mpg if you try hard. If
you do a lot of stop-start town driving you'll get significantly more.

The Mk 3 not Mk 2.

"The Natural Philosopher" wrote in message
...
harry wrote:
On Jan 2, 6:07 pm, Andy Champ wrote:
On 31/12/2011 11:26, The Natural Philosopher wrote:



I don't know where you've been, but lots of conventional IC engined
cars
now use their alternator to store energy when slowing.
No they dont.
BMW call it "Efficient Dynamics". I suspect it makes F-all difference
though - just takes a little load off the engine while under load,
rather than storing it to accelerate with.

Andy

Well they would have to have somewhere to store this energy.

I seem to remember that BMW were working on an ICE that had few
mechanical parts, every thing was electric. Water pump, oil pump,
valves, cooling fan, steering, AC, fuel injection. They were using
heat from the exhaust with a thermopile to charge the battery,
therefore no alternator.
There was only a crankshaft, con rods valves and pistons. No camshaft.

Dunno what became of it.

the realised like all renewable energy it was an expensive piece of ****e,
probably.

It wasn't expensive. The original idea was to have a larger alternator with
a clutch and larger battery. The alternator only engaged on braking or
engine over-run clawing back some kinetic energy. On acceleration or
start-up the alternator would not engage. On start up the electric cooling
pump would not engage either and would not until the engine reached a
certain temperature. The alternator would only engage on acceleration when
the battery was down and then it would come in to top up occasionally - as
in Mway driving. All this took extra stress off the engine when starting,
so a smaller starter is needed and less stress on the battery on starting as
well. They were supposed to extend it, to cut out the engine in town when
stopped at lights.

Variable speed electric water pumps work very well only at the speed needed
for cooling. In stopped traffic, it could actually be at full speed, so no
hot spots in the engine.

Having all ancillaries electric makes the Internal Combustion engine, a
crock at best, operate more efficiently. It also means that an engine can
be slightly downsized as acceleration is brisker. So an improvement all
around. But a crock is crock, it is just polishing a crock.

On 03/01/12 12:32, Doctor Drivel wrote:

"funkyoldcortina" wrote in message
...
On 26/12/11 11:31, Doctor Drivel wrote:

"Dave Plowman (News)" wrote in message
...

It's common to give the very best MPG that can be achieved under ideal
conditions.

The Mk 3 Pirus get 75mpg in average driving. This is hard for senile fools to
comprehend.

No, it doesn't.

But it will get about 50mpg without trying and 60mpg if you try hard. If
you do a lot of stop-start town driving you'll get significantly more.

The Mk 3 not Mk 2.

Yes, I'm talking about the Mk 3 as I drive one regularly (though it's not
mine or my company's).

In article ,
funkyoldcortina wrote:
The battery can charge while the petrol engine is running - the engine
will run at an RPM suitable for maximum efficiency, not just enough RPM
to drive the wheels. "Spare" power at this RPM goes into recharging the
battery

There is no such thing as 'spare power' under these circumstances. The
only truly free energy in this context is that recovered instead of using
brakes.

--
*A conscience is what hurts when all your other parts feel so good *

Dave Plowman London SW
To e-mail, change noise into sound.

"funkyoldcortina" wrote in message
...
On 03/01/12 12:32, Doctor Drivel wrote:

"funkyoldcortina" wrote in message
...
On 26/12/11 11:31, Doctor Drivel wrote:

"Dave Plowman (News)" wrote in message
...

It's common to give the very best MPG that can be achieved under ideal
conditions.

The Mk 3 Pirus get 75mpg in average driving. This is hard for senile
fools to
comprehend.

No, it doesn't.

But it will get about 50mpg without trying and 60mpg if you try hard. If
you do a lot of stop-start town driving you'll get significantly more.

The Mk 3 not Mk 2.

Yes, I'm talking about the Mk 3 as I drive one regularly (though it's not
mine or my company's).

Around central London they get approx 75mpg. Even 5th Gear confirmed that
saying 72.4mpg "average":
http://www.youtube.com/watch?v=ml2sPeCQIJw

They lauded the car on its eco credentials.

On Jan 2, 10:27*am, John Williamson
wrote:
dennis@home wrote:

"Tony Bryer" wrote in message
.. .
On Sun, 01 Jan 2012 18:43:53 -0000 Polygonum wrote :
How much would it cost to bore, says, one mile of dual tunnel capable
of carrying two tracks, and how much for one tunnel large enough for
both tracks? Make any assumption you like about the specification of
the trains - e.g. Circle line standard.

Wouldn't one larger tunnel have safety issues - thinking of the Channel
Tunnel where you escape from the running tunnels into the service tunnel

I think the biggest problem would be air flow caused by passing trains...
you would probably need to build a central wall to control it. This
would also make it much stronger.

Double track rail tunnels on the main line network don't bother, even on
high speed lines. Underground networks often use the passage of the
trains as pistons to help the ventilation in the network.

When most of the main line tunnels were built, the main problem with
ventilation was getting enough airflow to get rid of the smoke and
steam, which is why you can follow the line of most of them by walking
between the vents. In steam days, you would see columns of smoke rising
from the vents, and could watch the progress of a train through the tunnel.

Not just the smoke in extreme cases
http://baldbrummy.typepad.com/amateu...fire-stub.html
A testament to the original over-engineering that the tunnel survived.

MBQ

In article ,
Doctor Drivel wrote:
Yes, I'm talking about the Mk 3 as I drive one regularly (though it's
not mine or my company's).

Around central London they get approx 75mpg. Even 5th Gear confirmed
that saying 72.4mpg "average":
http://www.youtube.com/watch?v=ml2sPeCQIJw

They lauded the car on its eco credentials.

I'm surprised you've never read the Prius Forum. Where real people talk
about their real cars. In the US, about 40 mpg is the norm for town use.
And even allowing for the US gallon being smaller it isn't in the 75 mpg
ballpark. Nor do any of the official MPG figures quote 75 mph - even
although they are extremely flattering to this design of power train.

--
*Hard work has a future payoff. Laziness pays off NOW.

Dave Plowman London SW
To e-mail, change noise into sound.

"Man at B&Q" wrote in message
...
On Jan 2, 10:27 am, John Williamson
wrote:
dennis@home wrote:

"Tony Bryer" wrote in message
.. .
On Sun, 01 Jan 2012 18:43:53 -0000 Polygonum wrote :
How much would it cost to bore, says, one mile of dual tunnel capable
of carrying two tracks, and how much for one tunnel large enough for
both tracks? Make any assumption you like about the specification of
the trains - e.g. Circle line standard.

Wouldn't one larger tunnel have safety issues - thinking of the Channel
Tunnel where you escape from the running tunnels into the service
tunnel

I think the biggest problem would be air flow caused by passing trains..
you would probably need to build a central wall to control it. This
would also make it much stronger.

Double track rail tunnels on the main line network don't bother, even on
high speed lines. Underground networks often use the passage of the
trains as pistons to help the ventilation in the network.

When most of the main line tunnels were built, the main problem with
ventilation was getting enough airflow to get rid of the smoke and
steam, which is why you can follow the line of most of them by walking
between the vents. In steam days, you would see columns of smoke rising
from the vents, and could watch the progress of a train through the
tunnel.

Not just the smoke in extreme cases
http://baldbrummy.typepad.com/amateu...fire-stub.html
A testament to the original over-engineering that the tunnel survived.


The ventilation shaft added to the fire acting as a chimney. Having only
electric locos and no vent shafts means the tunnel could have been sealed
from the air at both ends using JCBs. Then the fire would be extinguished.