In article ,
(Clive) wrote:

In message ,
Colin Rosenstiel writes
Have you not heard of induction motors?
Yes, but how much of the total electric traction in our country uses
these? I suspect it is only the newest solid state controlled
equipment.

I.e. any new equipment.

--
Colin Rosenstiel

On Tue, 08 Nov 2005 14:31:08 GMT, Adrian wrote:

David Bradley ) gurgled happily, sounding much
like they were saying :

Please explain further. In my book a trolleybus IS zero polluting.

Your book is - at best - skimpy.

Where does the electricity come from?

As a former CEGB / NGC employer I can answer that question in
exceptional detail. In can see where you are coming from by
suggesting that the production of electricity is sometimes less than
enviromental friendly but equally can be derived from renewable
sources such as wind power or hydro sources.

And what percentage of UK grid electricity is?

http://www.dti.gov.uk/energy/inform/...ity/dukes05_5_
6.xls

2004 -
Coal - 36.9%
Oil - 1.34%
Gas - 34.24%
Nuclear - 21.49%
Renewable Thermals - 3.34% (Burning biofuels and non-biodegradable
waste)
Other Thermals - 1.83% (Coke oven gas, Blast furnace gas, Waste products
from chemical processes)
Hydro - Natural Flow - 0.5%
Hydro - Pumped Storage - 0.27%
Other Non-Thermal - 0.2% (Wind, Wave, Solar)

So somewhere in the region of sod all. Or, to put a number on it,
renewables make 4.31% of the UK's electricity.

A lot better than I expected, I will admit. But still not much.
Especially as any ramp-up in demand will be met by the non-renewables,
as the renewables are stretched to provide the current amount.

The power might even have been provided from another country but
however it was produced, and where ever it originated from, the
product does not come with any kind of labelling for your average user
to be able to determine its source.

Indeed. So it's not quite right to say it's "zero-polluting", is it?

The right combination of circumstances can therefore have a trolleybus
operating on a fuel that can be considered to be entirely zero
polluting and to suggest that can't happen is bunkum.

Indeed.

However, to suggest that it's *likely* to happen is equally bunkum.

In any event I would certainly prefer a trolleybus service running
past my front, especially at night, rather than the cleanest of
diesel buses.

Ah, the "I don't live next door to a powerstation, so they don't
matter" NIMBY line.

Obviously I have preferences were I wish to live [who doesn't?], but then you
are suggesting that the air is less pure around a power station than at the
kerb side in west London. Catch up on the facts and you will find this not so,
and indeed the air quality is at dangerous levels over in east London,
especially around the Ilford area!

Yet again I have to wearily point out the difference between the gross
pollution, the point of delivery from diesel buses (in addition to the wider
global pollution from the oil industry) and the admitted element of global
pollution from power stations. However, I would, however, draw your attention
to url http://www.tfwl.org.uk/media/drax.jpg where I have posted a media
cutting from the Financial Mail regarding the base load coal fired power
station (or rather two stations, with space for a future third, grouped around
a single 3-flue chimney) at Drax, This is said to be one of the cleanest coal
fired power stations in the UK. It didn't start out that way until the
Scandinavians blamed British power station gases, particularly the main
generating area in the Humber basin (including Drax) for acid rain carried on
prevailing SW winds denuding their forests and killing their river fish.

Considerable sums have been spent in cleaning up the flue gases from all power
stations in recent years, and while pollution levels are not at zero, the
small amount of damage done to the environment it is at least a considerable
distance away from areas where population congregates.

Trolleybus services passing my front door would be quiet and using a power
source that could be entirely zero polluting or at the very worst much kinder
to the environment than a diesel bus ever could be. If that makes me a NIMBY
then so be it. Trolleybuses are the least polluting transit vehicle there is;
maybe not exactly at zero but close enough to say so.

David Bradley

"Adrian" wrote in message
. 244.170...
d ) gurgled happily, sounding much like they were saying :

Not to mention (Bendis) more fuel-efficient (due to their modern
engines) (than RMs)

Don't forget that all recent service RMs were rebuilt mechanically
only a very few years ago, and meet at least Euro2 emission
standards.

Their engines aren't new designs, hence their massive noise. And
emission standards have little to do with fuel economy

More to do with it than "noise" - and the drive-by noise is more to do
with
the fact there isn't acres of (heavy) sound deadening.

And the fact their engines are massive diesels right at the front of the
bus, exposed on 4 sides to the street.

The Citaro G Bendis are Euro3, but they *CERTAINLY* won't be "more
fuel efficient", due to the fact they weigh ELEVEN TONS more than a
Routemaster.
That's before you consider the wasted time and fuel in traffic due to
the unwieldy extra length where a Routemaster would get through.

That doesn't make much sense. You can't just look at the weight and
make all your conclusions from that. The engines on the new busses,
and all the bits connecting them to the wheels, are brand new designs
(compared to the RMs).

You forget that all RMs were re-engined within the last decade or so,
hence
the Euro2 compliance.

Re-engined does not mean they have brand-new engine designs. The amount of
legacy requirements for any engine replacement for such an old vehicle would
mean it can never be 100% new.

As far as the weight goes, it costs fuel to drag that much lard about.

Most emissions are expressed in parts per million, Burning far more fuel
means that far more millions of parts are emitted, which means that far
more pollutants are emitted.

But if we're talking about efficiency, then it's parts per million per
traveller, right? And, not forgetting bendy busses are FAR more aerodynamic
than RMs, even with their flat fronts (as only one floor is having to cut
through the air, as opposed to the RM's two.

"Wasted time and fuel in traffic"? Bendy busses can overtake traffic RMs
would struggle to.

Indeed. But the excessive length makes for big problems elsewhen.

Sure, if they were going down Lombard in San Francisco, they might have some
problems.

I've used lots of RMs and lots of bendy busses, and the two aren't even
comparable when it comes to speedy driving. Bendy busses out-accelerate
RMs, which counts for everything in London traffic.

Not when a bus can't get through the junction no matter how quickly it
accelerates, because it would end up blocking it solid. And when there's
that many passengers standing, is fast acceleration a good thing? One
thing's for certain, accelerating 18ton of bus plus another 10ton of
people
quickly uses a LOT of fuel.

Doing the same with a worse-performing engine and heavy-weight chassis
quickly uses a lot of fuel, too.

"Colin McKenzie" wrote in message
...
d wrote:
..... You can't just look at the weight and make all your conclusions
from that. The engines on the new busses, and all the bits connecting
them to the wheels, are brand new designs (compared to the RMs). "Wasted
time and fuel in traffic"? Bendy busses can overtake traffic RMs would
struggle to. I've used lots of RMs and lots of bendy busses, and the two
aren't even comparable when it comes to speedy driving. Bendy busses
out-accelerate RMs, which counts for everything in London traffic.
Force = mass x acceleration. Ye canna break the laws of Physics. I already
knew there's lots more mass in a bendy - now you're saying there's more
acceleration too?

I know all about Mr. Newton's laws, thanks. If we're talking about
efficiency, you can't just look at f=ma and expect to know exactly what's
going on. That's ridiculous. Look at how efficient the engines are. If
the engine generates force more efficiently than the RMs, your whole
assertion is thrown into question.

I'd be surprised if they get as much as 5mpg. In Central London buses
almost never travel at constant speed.

More guesswork.

Colin McKenzie

Who is "Mr. Newton"?

Marc.

d ) gurgled happily, sounding much like they were saying :

You forget that all RMs were re-engined within the last decade or so,
hence the Euro2 compliance.

Re-engined does not mean they have brand-new engine designs. The
amount of legacy requirements for any engine replacement for such an
old vehicle would mean it can never be 100% new.

Wrong. They were retro-fitted with then-current-design Scania or Cummins
engines.

And, not forgetting bendy busses are FAR more
aerodynamic than RMs, even with their flat fronts (as only one floor
is having to cut through the air, as opposed to the RM's two.

FFS, what speed are buses DOING round you? Aerodynamics really don't make
much of a difference at urban bus speeds.

"Wasted time and fuel in traffic"? Bendy busses can overtake
traffic RMs would struggle to.

Indeed. But the excessive length makes for big problems elsewhen.

Sure, if they were going down Lombard in San Francisco, they might
have some problems.

Or turning right at crowded London junctions. Or trying to fit into bus
stops next to some pillock's illegally parked van.

Doing the same with a worse-performing engine and heavy-weight chassis
quickly uses a lot of fuel, too.

Indeed. Heavy weight. 18ton vs 8ton.

wrote in uk.transport.london on 9 Nov 2005 07:44:04
-0800 ups.com:

Who is "Mr. Newton"?

"Who" is a Time Lord.

On Wed, 09 Nov 2005 13:30:55 GMT, "d" wrote:

Re-engined does not mean they have brand-new engine designs. The amount of
legacy requirements for any engine replacement for such an old vehicle would
mean it can never be 100% new.

Didn't some of the refurbs basically have a brand-new Dennis Dart
driveline including autobox etc?

Neil

--
Neil Williams in Milton Keynes, UK
When replying please use neil at the above domain
'wensleydale' is a spam trap and is not read.

Adrian wrote in
70.163:

d ) gurgled happily, sounding much like they were saying
:


FFS, what speed are buses DOING round you? Aerodynamics really don't
make much of a difference at urban bus speeds.

Of course they do! That's why buses come in threes - the back 2 are
slipstreaming. :-)

On Wed, 09 Nov 2005 19:09:21 GMT, (Neil
Williams) wrote:

On Wed, 09 Nov 2005 13:30:55 GMT, "d" wrote:

Re-engined does not mean they have brand-new engine designs. The amount of
legacy requirements for any engine replacement for such an old vehicle would
mean it can never be 100% new.

Didn't some of the refurbs basically have a brand-new Dennis Dart
driveline including autobox etc?


There are many different engines but essentially there seem to have
been two generations of new engines. The first generation of new
engines was fitted during the late 1980s/early 1990s, so they're now
fairly old engines. These were used with the original transmissions
and were, if anything, a bit noisier than the original engines.

The second generation got new engines and transmissions within the
last five years or so. From outside they are *much* quieter than the
earlier engines, and my impression is that the outside noise level is
no different to that of a new bus (OK - a bendy is quiet if you're
right in front of it but then you're a long way from the engine).

As I understand it only buses with the second generation of new engine
and transmission will be suitable for the heritage routes, and they do
meet the euro III emissions standards which have applied for the past
few years

Martin