"Dave Arquati" wrote in message
...
John Rowland wrote:

I can't help noticing that there is a continuous strip
of undeveloped river valley from Feltham Station to
Terminal 4. But I'm not sure if using PRT on this corridor makes
financial sense.

I'm also not sure that PRT is very suitable for this kind
of connection, where a lot of people will arrive (at the
PRT stop at Feltham) together from a train, but no-one
will arrive in between trains. The reverse direction is better,
because people arriving from planes don't bunch together quite so much
(given customs etc.).

But how many people actually arrive at Feltham aiming for Heathrow? The
special buses were withdrawn. I'm sure that more people would use a PRT link
to all five terminals, especially if Feltham was suitably renamed (Heathrow
Feltham?)

John Rowland wrote:
"Dave Arquati" wrote in message
...
John Rowland wrote:
I can't help noticing that there is a continuous strip
of undeveloped river valley from Feltham Station to
Terminal 4. But I'm not sure if using PRT on this corridor makes
financial sense.
I'm also not sure that PRT is very suitable for this kind
of connection, where a lot of people will arrive (at the
PRT stop at Feltham) together from a train, but no-one
will arrive in between trains. The reverse direction is better,
because people arriving from planes don't bunch together quite so much
(given customs etc.).

But how many people actually arrive at Feltham aiming for Heathrow? The
special buses were withdrawn. I'm sure that more people would use a PRT link
to all five terminals, especially if Feltham was suitably renamed (Heathrow
Feltham?)

I meant more that it would be a victim of its own success - if people
realise they can go to Feltham and get a near on-demand connection to
Heathrow, the services will become much more well-used, and since trains
run to Feltham fairly spaced out (every 15 mins?), that means that every
15 mins, a lot of people will arrive and demand a PRT vehicle (which is
not ideal for PRT, as it's more suited to dispersed arrival times).

At the other end of the scale, I rarely saw the Feltham bus link
advertised anywhere except in very small print on maps - contrast with
publicity for Reading RailAir, which seems to me to be fairly widely
advertised in comparison.

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

"Dave Arquati" wrote in message
...
John Rowland wrote:
"Dave Arquati" wrote in message
...
John Rowland wrote:
I can't help noticing that there is a continuous strip
of undeveloped river valley from Feltham Station to
Terminal 4. But I'm not sure if using PRT on this corridor
makes financial sense.
I'm also not sure that PRT is very suitable for this kind
of connection, where a lot of people will arrive (at the
PRT stop at Feltham) together from a train, but no-one
will arrive in between trains. The reverse direction is better,
because people arriving from planes don't bunch together
quite so much (given customs etc.).

But how many people actually arrive at Feltham aiming for
Heathrow? The special buses were withdrawn. I'm sure that
more people would use a PRT link to all five terminals,
especially if Feltham was suitably renamed (Heathrow Feltham?)

I meant more that it would be a victim of its own success -

I don't see how that can happen to PRT, unless they don't buy enough
vehicles or the station cannot board enough vehicles at the same time. The
crowd comes onto the front of the platform at Feltham, filling the (coupled)
pods from the front until 10 seconds has passed without any doors being
opened, and then all the doors would shut, and the occupied pods would
decouple from the unoccupied ones to zoom off to Terminal 4 as a single
train... the unoccupied ones would then move forward to the front of the
platform, ready for the stragglers or the next train, and giving room for
the pods arriving one at a time from T4 to couple on the back, after
depositing their payload at the short arrivals platform first. At T4, there
would be a little marshalling yard where the pods were regrouped to form
little trains heading for each other terminal/car park. Of course, in times
of low demand, single pods would fly about instead. Or have I got it all
wrong?

Building multi-storey car parks at Feltham would probably improve the case
for the branch. Ideally, you want people to park in the nearest car park to
their house and get the PRT to their terminal, instead of parking in the car
park nearest to their chosen terminal.

In message , at 22:31:09 on Wed,
15 Mar 2006, John Rowland
remarked:
At T4, there would be a little marshalling yard where the pods were
regrouped to form little trains heading for each other terminal/car
park. Of course, in times of low demand, single pods would fly about
instead. Or have I got it all wrong?

What makes you think that the pods can run as a train? They seem to be
self-powered, so I reckon there's probably a minimum distance between
each one when running. The pods would also need to take people to T5,
and possibly T1-3 as well.
--
Roland Perry

Roland Perry wrote:
In message , at 22:31:09 on Wed,
15 Mar 2006, John Rowland
remarked:
At T4, there would be a little marshalling yard where the pods were
regrouped to form little trains heading for each other terminal/car
park. Of course, in times of low demand, single pods would fly about
instead. Or have I got it all wrong?

What makes you think that the pods can run as a train? They seem to be
self-powered, so I reckon there's probably a minimum distance between
each one when running. The pods would also need to take people to T5,
and possibly T1-3 as well.
--
Roland Perry

ULTra pods operate independently, with no ability to couple together. I
think the design headway is something like 2 or 3s.

Mike

Roland Perry wrote:
In message , at 22:31:09 on Wed,
15 Mar 2006, John Rowland
remarked:
At T4, there would be a little marshalling yard where the pods were
regrouped to form little trains heading for each other terminal/car
park. Of course, in times of low demand, single pods would fly about
instead. Or have I got it all wrong?

What makes you think that the pods can run as a train? They seem to be
self-powered, so I reckon there's probably a minimum distance between
each one when running. The pods would also need to take people to T5,
and possibly T1-3 as well.

ULTra pods are self (battery) powered, with no ability to couple
together. The theory is that the headway is as short as 2 or 3s, and
they recharge when stationary, awaiting the call.

Mike

In message , at 10:24:33 on Thu,
16 Mar 2006, John Rowland
remarked:
ULTra pods are self (battery) powered, with no ability to couple
together. The theory is that the headway is as short as 2 or 3s, and
they recharge when stationary, awaiting the call.

Oh, okay. With such short headways, coupling would be unnecessary. How can
they get away with such short headways when trains can't?

It's not that different to a fairground ride. One of the scenic tours,
rather than a roller-coaster, though.
--
Roland Perry

In message , Dave Arquati
writes

John Rowland wrote:

Oh, okay. With such short headways, coupling would be unnecessary.
How can they get away with such short headways when trains can't?

I think they're rubber-tyred and very light.

Also, computer-control of the entire system means that if the vehicle in
front is braking, the one behind can react within a fraction of a
second.
--
Paul Terry

"Paul Terry" wrote in message
...
In message , Dave Arquati
writes

John Rowland wrote:

Oh, okay. With such short headways, coupling would be unnecessary. How
can they get away with such short headways when trains can't?

I think they're rubber-tyred and very light.

Also, computer-control of the entire system
means that if the vehicle in front is braking,
the one behind can react within a fraction of a second.

I would hope that the vehicle behind would start braking first, and only
when the brakes on that are known to be working would the vehicle in front
start braking.

In message , at 12:23:00 on Thu, 16 Mar
2006, Paul Terry remarked:
Also, computer-control of the entire system means that if the vehicle
in front is braking, the one behind can react within a fraction of a
second.

Ah! The fabled "moving block" signalling that seems such a challenge to
get implemented on the railways.
--
Roland Perry