"Michael R N Dolbear" wrote in message
news:01ca31a0$aa1aec60$LocalHost@default...
wrote
If they had double deckers they wouldn't need 24tph. Even if they're
not
planning UIC gauge trains, building the tunnels to UIC gauge would
cost little
if anything extra. But this is britain, planning for unforseen future
needs is
frowned upon as we all know.
Increased dwell times would mean longer journeys at /any/ tph and and
lower tph would mean longer wait times too.
Any designs for double decker /platforms/ to go with double decker
trains ?
"Plenty of room on top" (VBG).
--
Mike D
Sorry to have caused some "heat", guys.
I said 'twas a pity they aren't to make provision for this as a stage 3, for
future capacity growth. I know Stage 1 will be fitted for 200m single deck,
triple-door-openings per-side trains at Day 1, and they say Stage 2 will be
fitted for 240m trains. The platform tunnels will be built at Stage 1 to, I
suspect 250m total length - but not fully fitted. The trains will have to be
dedicated to XRail at first, though later builds for Overground and Inner
London TOC services might also be built to the same dimesions and door
positions and thus be potentially Xrail compatible.
The increase in size needed to achieve well-type DD in OHLE lines in UK is
actually fairly modest - the main thing being room for "hips" and
"shoulders", so a non-circular shape would be best. I believe X-Rail are
mooting non-circular tunnels. The normal height of 3965mm is almost
sufficient, perhaps 4000mm to 4050mm would give scope for further increases
in median tallness of the British railway commuter population. It's the
shoulders and hips where the designs would be cramped for kinematic envelope
in current loading gauges. One wouldn't need any of the UIC gauges as such,
just sufficient to accommodate a 2895/2900-ish mm width from about 200mm
above rail to about 3300mm above rail.
As regards tunnelling costs, when I put the case in Perth, Western Australia
for using 3rd rail through the underground and Narrows Bridge sections - the
first to allow smaller diameter tunnels and the 2nd for aesthetic reasons -
I was informed by a Mr Mann, the project's chief engineer, that the cost
differential between bored 4.6m tunnels and bored 6m tunnels was negligible.
This is in an area of saturated dune sands, clays and silts with little
sedimetary rock and no hard rock - so tunnel lining performance parameters
would be critical. IMHO, I was served bureaucratic claptrap, but if he is
correct then XRail could future proof without blowing their business case.
I was also informed that the cost of dual voltage stock was an order of
magnitude more expensive. The implication being that whatever might be saved
in tunnelling cost would be blown by higher rolling stock cost - which is a
periodically recurring cost rather than a one-off. Bombardier won the
contract to supply the traction equipment for them. As these trains have
been built and delivered this decade, how does that assertion match with
UTL/UKR contributors' knowledge of the comparative cost of AC-only, AC/DC
and DC-only versions of the same base model UK EMU in the same period?
Again, I put this idea into play as a future-proofing concept, such that
when the "overground" sections are cleared to the let's call it UK "X2"
loading gauge, then the capability can be exploited to buffer growth in
numbers (and median size) of pax.
Cheers all
DW downunder