I stumbled across this plan (http://www.lrta.org/london-Hounslow.html),
involving a tram from Hammersmith to Heathrow along the A4. They say
that it would reduce traffic on the A4 by 20%, however I understand it
would take up one lane in each direction (33%) of the road capacity,
therefore *increasing* congestion.

I looked on alwaystouchout and I couldn't find the project!

There's also a Heathrow-Kingston tram mentioned too.

Paul Weaver wrote:
I stumbled across this plan
(http://www.lrta.org/london-Hounslow.html), involving a tram from
Hammersmith to Heathrow along the A4. They say that it would reduce
traffic on the A4 by 20%, however I understand it would take up one
lane in each direction (33%) of the road capacity, therefore
*increasing* congestion.

I looked on alwaystouchout and I couldn't find the project!

There's also a Heathrow-Kingston tram mentioned too.

These proposals were originated by the London Borough of Hounslow in
2002, and were launched not long before the local council elections.
See
http://www.hounslow.gov.uk/shownews?...27-02-2002.htm

They had come up with two routes that neatly served most parts of the
borough, without resolving key questions about the termini which lay
outside the borough. It was unclear whether, and if so how, the tram
would serve the Heathrow terminals, how it would get to Hammersmith
without taking lanes off the A4 or clogging up Chiswick High Road, and
how it would get to Kingston through fairly narrow roads and across the
Thames. In fact even the council admitted to me that the Kingston
branch would not be a priority for further investigation.

We haven't heard much about the scheme since then.

--
Richard J.
(to e-mail me, swap uk and yon in address)

I stumbled across this plan (http://www.lrta.org/london-Hounslow.html),
involving a tram from Hammersmith to Heathrow along the A4. They say
that it would reduce traffic on the A4 by 20%, however I understand it
would take up one lane in each direction (33%) of the road capacity,
therefore *increasing* congestion.

Which is simply wrong!

Normal car capacities (calculation guidelines values, real numbers are
significantly higher) are about 2000 cars/lane/hour.
Well let's say, that the cars have very high occupation (3 people per car,
which is way higher than the actual abt. 1,3) then we get a transport
capacity per lane per hour of 6000 persons per lane per hour.
A tram's capacity is abt. 22 thousand passengers per hour [1].
In the case of taking the car's value as their capaicity, it would still
reach only 10000persons/lane/hour.

Source [1]: Verkehrsclub Österreich (1999); Mobilität lernen - sicher und
umweltbewußt; Wien

regards
Tadej
--
.... aber auch bei Frauen hat das Großhirn tatsächlich eine Funktion ...
Selbst im wildestens Winterschlußverkaufrausch verstehen sie noch das Wort
"Kreditkartenlimit".
David Kastrup in d.t.r

"Richard J." wrote in message
. uk...
Paul Weaver wrote:
I stumbled across this plan
(http://www.lrta.org/london-Hounslow.html), involving a tram from
Hammersmith to Heathrow along the A4. They say that it would reduce
traffic on the A4 by 20%, however I understand it would take up one
lane in each direction (33%) of the road capacity, therefore
*increasing* congestion.

I looked on alwaystouchout and I couldn't find the project!

There's also a Heathrow-Kingston tram mentioned too.

These proposals were originated by the London Borough of Hounslow in
2002, and were launched not long before the local council elections.
See

http://www.hounslow.gov.uk/shownews?...27-02-2002.htm

They had come up with two routes that neatly served most parts of the
borough, without resolving key questions about the termini which lay
outside the borough. It was unclear whether, and if so how, the tram
would serve the Heathrow terminals, how it would get to Hammersmith
without taking lanes off the A4 or clogging up Chiswick High Road, and
how it would get to Kingston through fairly narrow roads and across the
Thames. In fact even the council admitted to me that the Kingston
branch would not be a priority for further investigation.

We haven't heard much about the scheme since then.

--
Richard J.
(to e-mail me, swap uk and yon in address)


Not a bad idea though and worth looking at.

The A4 from Chiswick roundabout all the way up to the Bath Road in Hounslow
is 3 lane with cycle path on either side for much of the way.
The H91 bus currently plies the route.
Obviously the Chiswick high street end and the Heathrow end would be
problematic.

But taking one of the lanes isn't too bad an idea. And perhaps using the
cycle lanes (which are seldom used)
There will be junctions and parts where you'll have to encroach on the third
lane if the cycle lane were used.
And there would also be problems with the roundabout at Ealing road and the
M4 slip.
but with some reworking it could be possible, it just needs some thinking
about.

but I doubt there will be much demand for the service. It could however
create demand.
But it wasn't so long ago that the H91 was a very poor frequency service
which rarely turned up on time
and did even run late or at the weekend. The improved H91 is doing a good
job, doubt they need a tram to replace it.

"Tadej Brezina" wrote in message
...
I stumbled across this plan (http://www.lrta.org/london-Hounslow.html),
involving a tram from Hammersmith to Heathrow along the A4. They say
that it would reduce traffic on the A4 by 20%, however I understand it
would take up one lane in each direction (33%) of the road capacity,
therefore *increasing* congestion.

Which is simply wrong!

Normal car capacities (calculation guidelines values, real numbers are
significantly higher) are about 2000 cars/lane/hour.
Well let's say, that the cars have very high occupation (3 people per car,
which is way higher than the actual abt. 1,3) then we get a transport
capacity per lane per hour of 6000 persons per lane per hour.
A tram's capacity is abt. 22 thousand passengers per hour [1].

Quite apart from the fact that this looks unbelievably high (22
trams per hour with 1000 pax each, how many pax can you get
in a single tram?) this assumes that you will get this number of
people to transfer mode.

In Britian this seems most unlikely even if you did run a tram
evey 2.5 minutes (which they wont).

tim

"tim (moved to sweden)" wrote in message
...
"Tadej Brezina" wrote in message
...

A tram's capacity is abt. 22 thousand passengers per hour [1].

Quite apart from the fact that this looks unbelievably high (22
trams per hour with 1000 pax each, how many pax can you get
in a single tram?)

ISTR trams can run with something like 40 second headways!

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes

"John Rowland" wrote in message
...
"tim (moved to sweden)" wrote in message
...
"Tadej Brezina" wrote in message
...

A tram's capacity is abt. 22 thousand passengers per hour [1].

Quite apart from the fact that this looks unbelievably high (22
trams per hour with 1000 pax each, how many pax can you get
in a single tram?)

ISTR trams can run with something like 40 second headways!

Perhaps they can for a short stretch of track, but I don't think
that I've ever seen anything close to this on the whole length of
a single line. Anything more than one tram about every 2 minutes
causes bunching at traffic lights [1] and stops. This bunching clears
when separate routes diverge, but if they all go to the same place
the service become unworkable at this frequency.

[1] and there will still be lots of these!

tim

In message , "tim (moved to sweden)"
writes

Perhaps they can for a short stretch of track, but I don't think
that I've ever seen anything close to this on the whole length of
a single line. Anything more than one tram about every 2 minutes
causes bunching at traffic lights [1] and stops.

The Cross River Transit tramway plans for a 90-second headway through
the central section. On most modern tram systems, the approach of a tram
will clear traffic lights in its favour, so these rarely cause delays -
stops do, of course.

This bunching clears when separate routes diverge,

Indeed - CRT has two branches north and two branches south, so 90
seconds may be realistic.

but if they all go to the same place the service become unworkable at
this frequency.

I've certainly seen trams running at something like a 40-second headway
in parts of Prague - but I've also been stuck in some ginormous
tram-jams in that city, too!

--
Paul Terry

Paul Terry wrote:
In message , "tim (moved to sweden)"
writes

Perhaps they can for a short stretch of track, but I don't think
that I've ever seen anything close to this on the whole length of
a single line. Anything more than one tram about every 2 minutes
causes bunching at traffic lights [1] and stops.


The Cross River Transit tramway plans for a 90-second headway through
the central section. On most modern tram systems, the approach of a tram
will clear traffic lights in its favour, so these rarely cause delays -
stops do, of course.

Indeed - priority should be given to CRT throughout its whole route,
with the exception of the crossing of the Euston Road. The 90-second
frequency is the limit not for any spacing-related reason but because
firstly, this is the required timing for a light sequence at the Euston
Road/Eversholt Street junction to stop traffic locking up on the inner
ring road, and secondly to prevent excessive delay to the high number of
bus services crossing the route at the Strand and Holborn.

--
Dave Arquati
Imperial College, SW7
www.alwaystouchout.com - Transport projects in London

Paul Weaver wrote:
I stumbled across this plan (http://www.lrta.org/london-Hounslow.html),
involving a tram from Hammersmith to Heathrow along the A4. They say
that it would reduce traffic on the A4 by 20%, however I understand it
would take up one lane in each direction (33%) of the road capacity,
therefore *increasing* congestion.

I looked on alwaystouchout and I couldn't find the project!

There's also a Heathrow-Kingston tram mentioned too.

I'm ashamed to say I missed these out because they seemed a bit unlikely
at the time. If I have time to put them in, I will, for completeness'
sake at least.

--
Dave Arquati
Imperial College, SW7
www.alwaystouchout.com - Transport projects in London