On Aug 18, 10:48*pm, "
wrote:
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.

Haha! Yes I meant Manor House....

It's very noticable at the moment, the dust...

On Aug 19, 4:33*pm, Railist wrote:
On Aug 18, 10:48*pm, "
wrote:





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.

Haha! Yes I meant Manor House....

It's very noticable at the moment, the dust...

There is a ventilation shaft between Manor House and Turnpike Lane so
that accounts for the 'whoosh'. As the dust you mention never ends up
in my cab the only thing that I think it can be is dust forced through
the ventilations fans in the roof of the train

upinthesky wrote:
On Aug 19, 4:33*pm, Railist wrote:
It's very noticable at the moment, the dust...

There is a ventilation shaft between Manor House and Turnpike Lane so
that accounts for the 'whoosh'. As the dust you mention never ends up
in my cab the only thing that I think it can be is dust forced through
the ventilations fans in the roof of the train


As you approach a ventilation shaft, the air in the running tunnel is
being forced along (by fans) in the same direction as the train. As
you pass the shaft, there is an abrupt change, in that the air outside
the train is now being forced along by fans in the opposite direction.

The sudden change to air that is coming at the train in the opposite
direction is the cause of the 'whoosh'. If that air is dust-laden, as
it usually is, that is the reason for the appearance of dust in the
train at that point.