On 18/08/2010 21:42, Richard J. wrote:
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.

I think the OP means between Manor House and Turnpike Lane as Mansion
House is on the Circle and District Lines and rather a distance away.

I thought that the Circle and District ran under Cannon Street between
Monument and Mansion House -- also a relative distance from Bank of
England vaults.