On Wed, 9 Apr 2008, Tom Anderson wrote:

On Wed, 9 Apr 2008, John B wrote:

Other interesting highlights:

* the trains must weigh less than 32 tonnes per coach

Is there an external driver for that requirement, or does it just come
from the Good Ideas Club at the ministry?

Oh, here we go:



4.1 Train mass (weight) is a critical parameter for whole system, whole
life cost because it affects both track maintenance and train energy
consumption. The Department and Network Rail both understand the virtuous
circle that can be created between track quality and train mass and
Network Rail is committed to improve track quality through its new
standards for maintenance.

4.2 The Department and Network Rail wish to work with Bidders to establish
a set of weight targets which can be set in the ITT. The Department is
aiming at a target of 256 tonnes (tare) per 162m train or 384 tonnes
(tare) per 243m train which is believed to be achievable.



A 162 metre train made of 20 metre cars is an 8 car train, and an 8 car
train which weights 256 tonnes has 32 tonne cars. If the supplier goes for
26 metre cars, six per train, they could weigh 42 tonnes. I have no idea
if there are reasons 26 metre cars can't be used; i believe the Southern
network has curves which preclude their use, but don't know if Thameslink
will use those.

tom

--
Yesterday's research projects are today's utilities and tomorrow's
historical footnotes. -- Roy Smith