On 29/06/2010 07:24, Paul Terry wrote:
In message , Basil Jet
writes

There is a drilling rig moving gradually down the middle of the Thames
at the mo. Today it was opposite Bermondsey Wall West. Allegedly it is
connected to some sort of sewer that they are building along under the
river...

No, it's just Thames Water drilling bore holes to determine the best
route for their sub-Thames Tunnel (West London to Beckton), prior to
public consultation on the plans beginning in September.

When eventually built, the tunnel will avoid the necessity of
discharging raw sewage into the Thames whenever there is more than 2mm
of rain.

Apparently it is the biggest sewage project in London since a chap
called Basil Jet tried to solve the problem 140 years ago.

It is seriously impressive stuff - a 9m diameter tunnel (compared with
6m for Crossrail), some 22km in length. Just a shame that they won't be
running double-decker trains through the tunnel when it's not raining.

I have no idea about such things, but I'd imagine a tunnel for carrying
rainwater beneath the Thames might not be built as sturdily as a tunnel
for carrying a railway.