David Splett wrote:
"Mait001" wrote in message
...

It's not the enforced closure of the line (although I fail to see
how installing a set of points and associated tunnel branching can
take all of 18 months)

I wondered this too, given that similar jobs for the Victoria and
Jubilee lines were done with closures lasting no more than a few
hours. However, I understand that there are major problems with
water at the site of the T5 junction, and for this reason a quite
complex engineering solution is required.

There are some details in this month's Modern Railways (page 52). The
ground at the junction site consists of water-bearing gravel, and
conventional techniques to build a step-plate junction would risk a
collapse of the existing tunnel. "At the site of the existing junction,
the ground is being opened up for the construction of a big coffer dam
extending 25 metres down. ... Once complete,this box will then hold the
junction." TBMs will drill towards the site from the T5 end, but the
final breakthrough will be done outwards from the box. Then they have
the task of restoring the concrete aircraft taxiway over the box. In
the circumstances, 20 months seems reasonable.

Did I fall asleep at LURS in November, or was this important information
omitted from the talk on the T5 extension?

Install lifts or escalators at Hatton Cross for a start!

It would actually be pretty cheap and easy to install lifts at HC.
Perhaps this is a missed opportunity.

Based on the Earl's Court experience, I'm not sure about the cheap and
easy bit. Anyway, a couple of small lifts wouldn't be very efficient at
dealing with lots of people with heavy baggage all arriving together.

The missed opportunity, in my view, is the failure to provide adequate
publicity of the step-free route via T123 and HEx. It is not mentioned
at all on the poster* (customers are advised to phone for advice on
step-free routes), though it is eventualy mentioned on the new "Heathrow
by Tube" leaflet** if you read far enough.

* http://tube.tfl.gov.uk/pdf/Heathow-closure-poster.pdf

** http://tube.tfl.gov.uk/pdf/Heathrow-T4-%20leaflet.pdf

--
Richard J.
(to e-mail me, swap uk and yon in address)