London Banter - View Single Post

David Bradley · November 7th 05, 06:53 PM posted to uk.transport.london

On 7 Nov 2005 07:23:36 -0800, wrote:

David Bradley wrote:

On Mon, 7 Nov 2005 11:12:17 -0000, wrote:

Now maybe you just happen to like bendy-buses with overhead power lines
for their own sake? But experience seems to show that simply sticking
bendy buses onto already overcrowded roads doesn't reduce congestion. I
don't see how they're going to fix that problem by just adding some ugly
power lines to the bus.

40 metre long trains, TWICE the length of bendybuses, running along Uxbridge
Road is really going to make a difference for the better or worse? Your call
to explain that one away.

Perhaps it is, but it doesn't alter the fact that you haven't answered
the question.

Well let's have a go then although I have never said anything about using
bendy trolleybuses although it's fair to assume that is what will be used.

TfL have evidently proposed tram segregation through various junctions in an
attempt to insulate the trams from junction congestion, whereas this is less
important for trolleybuses with their flexibility of manoeuvre and ability to
steer round obstructions. In any case, even if the needs and benefits were the
same for trams and trolleybuses once implemented, there remains
(1) the huge disparity in construction cost and time and related disruption as
between trams and trolleys, and
(2) the trolley advantage of getting the benefits of electric traction several
years earlier through much quicker construction and correspondingly earlier
opening date.

If there's to be no segregation and priority anywhere along the tramroute it's
hard to see what benefit a hugely expensive and disruptive tram scheme could
possibly have over a much cheaper and virtually disruption-free trolley
scheme, even ignoring the huge cost diffrential.

Considering the overhead aspect, a tramway service will use a pantagraph
system for current collection. The traction wires require to be at a
significant tension for the contact wire to be almost horizontal and there is
considerable upward pressure from the pantagraph itself. Such forces need
some quite chunky traction support post which are invarably girders and
horizontal "scaffolding poles" as the primary support. Hardly asthetically
pleasing and yet it seems to be acceptable because it is a tramway.

On the otherhand trolleybus current collection methods use twin booms wich are
more tollorant of the contact wires which are at a lower tension than that for
a tramway. Consequently lighter traction support poles can be used. The
amount of actual wiring in the sky is not significantly different between
either system.

There are huge benefits from having electric buses instead of diesel buses
that more than outweigh the visual intrusion of overhead wiring and booms on
the top of vehicles, most of which are attributed to tramway operation.
However if your desire is to have diesel trams, so be it and sod the
enviroment.

Now it's about time you made your position clear of which mode of transport
you prefer and why.

David Bradley