Railist wrote on 18 August 2010 17:11:33 ...

One other thing: between Mansion House and Turnpike Lane, there is
this "whoosh" noise and the front carriage receives a sprinkling of
fine dust. Any idea why this happens?

It's because they drove the new tunnel to Mansion House a bit too close
to the Bank of England vaults. It's just gold dust. Nothing to worry
about.
--
Richard J.
(to email me, swap 'uk' and 'yon' in address)