On Fri, 07 Jul 2006 12:38:32 +0100, congokid wrote:

In article na.org.au,
Matthew Geier writes

between stations on at least some of the older trains on the Cityrail
system. This year the trains I travelled on there appeared to be newer
and had air conditioning.

Nope. Probably only 2/3 of the fleet is actually air conditioned. All are
power doors though.
If it has opening windows it isn't air conditioned. There is no provision
for opening the windows on Air conditioned stock.

One thing I have noticed, and I could be imaging things (or just getting
older :-), is that as the proportion of trains with air-conditioning has
been increasing, the Sydney city tunnels are getting hotter.
Presumably with each train dumping several kw extra of waste heat into
the tunnels it's raising the average temperature.

It's probably no so much an issue with the Sub-Surface lines with their
larger tunnels and frequent 'smoke vents', but I could see this being a
serious issue with the deep tube trains - if you fit air conditioning to
any new build rolling stock, just where is the AC system going to dump
it's waste heat ?. The tubes are already too hot. A serious amount of
civil engineering would be needed to improve air-flows through the tubes
to carry the waste heat off. (And probably electrical works to increase
the capacity of the traction power network to take the extra electrical
load of the air conditioning plant on each train).

The tube tunnels themselves need some sort of cooling system fitted
before even thinking about the trains.
I seem to recall somewhere that pumping chilled water through pipes
buried in the platform has been tried at at least one LU station.