[sustran] Some slightly positive thoughts on metro etc

[Kerry Wood]

Could this discussion be beginning to slide towards metro bashing?

We agree that London or Pairs (or Mumbai, although that is more like suburban
rail) cannot just rip out their systems. But other cities are growing and will
be -- or already are-- as big as these three. Will these growing cities never
need metro?

Tony Ridley describes 3 three essential pre-requisites for light rail, but they
probably apply to any large transport infrastructure ("Light Rail - technology
or way of life" TM Riddle ICE Transport  5/1992):

-There must be political consensus regardless of the means of finance
- It must be part of an urban transport strategy
- There must be a clear decision-making framework

I hesitate to add anything to this, but I can't resist:

-  Don't pick your technology too soon

When the politicians say "light rail," "metro," "busway" or even "monorail",
assume (unless it is a simple extension of an existing system) that they mean
the four Hs: High quality, High capacity, Highly integrated, Hopefully
affordable.

If you want to shift 50 000 passengers an hour ( and especially if your city is
sitting on London Clay) a metro is probably a good idea, If 10 000 an hour is
enough and tunnelling is difficult, stay on the surface, with maybe the odd
cut-and-cover underpass where it is really needed.

Two parallel light rail lines might do the same job as a metro: say up to1000 m
apart in the CBD, 2 or more km apart further out. But if a light rail route is
to shift 25 000 / hr it needs very long trains, so cross streets might have to
be closed to fit stations in. It also needs a lot of junction time: a train
every 45 seconds (both ways), each occupying every junction for say 12 - 25
seconds. What will that do to POB (plain old bus) routes trying to cross the
light rail routes? Or to freight transport? If you are moving that many people
on a daily basis, some of them will be travelling a long way: will on-street
light rail be fast enough to compete with cars?

London put in a too-light light rail system in Docklands (because it was built
down to a price), rebuilt it at enormous expense to a semi-metro, then put in a
real metro through broadly the same area. Starting with a less metro-adverse
approach might have been cheaper in the end.

If you have political consensus, how do you check for cooking the numbers?


--
Kerry Wood  MICE  MIPENZ  MCIT
Transport Consultant
1 McFarlane Street, Wellington 6001, New Zealand
Phone + 64  4  971 5549