I have not heard this anywhere else on the Underground except at
Turnham Green

Listen carefully and you'll hear it at just about any over-ground tube
station where there is a log stretch of unbroken rail (ie. no
points/crossovers). I've heard it on just about every Piccadilly,
District and Central line open-air station I've ever used. And IME the
faster the train is going the more pronounced the noise. Clearly what
is happening is that the vibration of the train is setting up a
resonance in the rail, which will travel some way ahead of (and behind)
the train. The sound is there, but IME less pronounced, at sub-surface
stations -- probably because the rails are held more tightly on the
concrete sleepers/floors so the resonance is better damped compared with
over-ground sleepers and ballast. Also listen carefully and I think
you'll find the sound is also Doppler shifted.

*Keith*
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"Keith Marshall" wrote in message

I have not heard this anywhere else on the Underground except at
Turnham Green

Listen carefully and you'll hear it at just about any over-ground tube
station where there is a log stretch of unbroken rail (ie. no
points/crossovers). I've heard it on just about every Piccadilly,
District and Central line open-air station I've ever used. And IME
the faster the train is going the more pronounced the noise. Clearly
what is happening is that the vibration of the train is setting up a
resonance in the rail, which will travel some way ahead of (and
behind) the train. The sound is there, but IME less pronounced, at
sub-surface stations -- probably because the rails are held more
tightly on the concrete sleepers/floors so the resonance is better
damped compared with over-ground sleepers and ballast. Also listen
carefully and I think you'll find the sound is also Doppler shifted.

Presumably the sound seems louder because the Piccadilly Line trains are
normally non-stopping and running through the station relatively fast. There
aren't many other stations with Tube trains passing through at speed.

I also wondered if the steel girder bridge immediately to the west of the
station plays any part in the noise?

"Nigel Pendse" writes:

Presumably the sound seems louder because the Piccadilly Line trains are
normally non-stopping and running through the station relatively fast. There
aren't many other stations with Tube trains passing through at speed.

Jubilee Line between Wembley and Finchley Rd (IIRC the noise from Met
Line trains is the same).

I also wondered if the steel girder bridge immediately to the west of the
station plays any part in the noise?

It probably gives the Turnham Green sound a unique aspect.

jasonr (Jason Rumney) @ f2s.com wrote in message

"Nigel Pendse" writes:

Presumably the sound seems louder because the Piccadilly Line trains
are normally non-stopping and running through the station relatively
fast. There aren't many other stations with Tube trains passing
through at speed.

Jubilee Line between Wembley and Finchley Rd (IIRC the noise from Met
Line trains is the same).

I meant Tube in the specific sense of LU's trains for deep bore tunnels. I
think sub-surface LU stock (A, C or D stock) do make a different sound,
presumably because they're a bit heavier and also move differently on their
(softer?) suspensions. The firmer suspensions of Tube stocks probably excite
different resonances.

"Nigel Pendse" writes:

I meant Tube in the specific sense of LU's trains for deep bore tunnels. I
think sub-surface LU stock (A, C or D stock) do make a different sound,
presumably because they're a bit heavier and also move differently on their
(softer?) suspensions. The firmer suspensions of Tube stocks probably excite
different resonances.

It is a long time since I was on that stretch of Jubilee Line, so you
might be right. District line trains make roughly the same noise as
Picadilly approaching the station though. OTOH, I can definitely hear
the difference between District line trains and North London line
trains at Gunnersbury.

jasonr (Jason Rumney) @ f2s.com wrote:
"Nigel Pendse" writes:

I meant Tube in the specific sense of LU's trains for deep
bore tunnels. I think sub-surface LU stock (A, C or D
stock) do make a different sound, presumably because
they're a bit heavier and also move differently on their
(softer?) suspensions. The firmer suspensions of Tube
stocks probably excite different resonances.

It is a long time since I was on that stretch of Jubilee
Line, so you
might be right. District line trains make roughly the same
noise as
Picadilly approaching the station though. OTOH, I can
definitely hear
the difference between District line trains and North
London line
trains at Gunnersbury.

Perhaps someone should release a "Best Of" album?

"Cast_Iron" wrote in message
...
jasonr (Jason Rumney) @ f2s.com wrote:
"Nigel Pendse" writes:

I meant Tube in the specific sense of LU's trains for deep
bore tunnels. I think sub-surface LU stock (A, C or D
stock) do make a different sound, presumably because
they're a bit heavier and also move differently on their
(softer?) suspensions. The firmer suspensions of Tube
stocks probably excite different resonances.

It is a long time since I was on that stretch of Jubilee
Line, so you
might be right. District line trains make roughly the same
noise as
Picadilly approaching the station though. OTOH, I can
definitely hear
the difference between District line trains and North
London line
trains at Gunnersbury.

Perhaps someone should release a "Best Of" album?

Please, not even in jest...
--
Cheers, Steve.
If The Good Lord had meant for us to be fiscally prudent, He would not have
given us the platinum credit card...
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