In message
Matthew Geier wrote:

On Thu, 07 May 2009 10:56:46 +0100, rail wrote:


Not mentioned for a very simple reason, battery technology is just not
up to the job, nor is it likely to be in the forseeable future. While
it is a feasable option for low density occasional traffic, eg the
battery luggage vans that used to be used at Dover docks, it just can't
cope with the sort of service that Crossrail will be operating.

Why add the extra weight and expense of a battery pack that can run the
train at speed, with full auxiliaries running ( many kw of air-
conditioning), so a large heavy battery pack, when you can put up a wire
and feed it 'mains' power ?

Batteries will develop and get cheaper ,

That's not a given, there has been one major change in battery technology in
the last 50 years and despite the amount of R&D being thrown at it, there's
no sign of another one happening anytime soon, regardless of how desirable it
may be perceived to be.


Given a train can be easily powered by a power rail or overhead lines, I
can't see the advantage of adding the extra weight of a battery pack. If
you are going to add that sort of weight, chuck in a diesel engine.

Which won't need replacing in 18 months.

--
Graeme Wall

This address not read, substitute trains for rail
Transport Miscellany at www.greywall.demon.co.uk/rail