I live in Richmond and take the District Line into Central London
about once a week. Sometimes I change trains at Turnham Green to go to
Ealing Broadway. When I am at Turnham Green, I have noticed that the
tracks make strange noises when either a Piccadilly or a District
train is approaching. No matter how fast the incoming train is
traveling, the tracks twang, rattle and vibrate like huge springs are
being snapped back and forth. Once the train has passed by, the sound
continues until the train is well away from the platform.

I have not heard this anywhere else on the Underground except at
Turnham Green and some of the stations east of it (the tracks at Earls
Court and Victoria make the sound, but it's much more faint than at
Turnham Green). Does anyone have a clue as to what I'm hearing?

Brad Chapman

Brad Chapman:
When I am at Turnham Green, I have noticed that the tracks make
strange noises when either a Piccadilly or a District train is
approaching [or leaving]. ... the tracks twang, rattle and vibrate
like huge springs are being snapped back and forth.

Does anyone have a clue as to what I'm hearing?

On some parts of the Toronto subway system, oversize concrete sleepers
are used. These are so wide that they form almost a continuous sheet
of concrete with only small gaps between them, and although the rail
fastenings are spaced as usual, each rail is fastened to each sleeper
in two places. I have heard that between these sleepers and another
layer of concrete underneath, there is some sort of rubber; I don't
know in what form exactly. And this track makes sounds very much like
Brad's description, except that I would have omitted the word "rattle".

So do the tracks around Turnham Green *look* any different than on
other parts of the Underground, these days? It's been some years since
I was there.
--
Mark Brader "Never re-invent the wheel unnecessarily;
Toronto yours may have corners."
-- Henry Spencer

My text in this article is in the public domain.

Mark Brader wrote:
Brad Chapman:
When I am at Turnham Green, I have noticed that the tracks make
strange noises when either a Piccadilly or a District train is
approaching [or leaving]. ... the tracks twang, rattle and vibrate
like huge springs are being snapped back and forth.

Does anyone have a clue as to what I'm hearing?

On some parts of the Toronto subway system, oversize concrete sleepers
are used. These are so wide that they form almost a continuous sheet
of concrete with only small gaps between them, and although the rail
fastenings are spaced as usual, each rail is fastened to each sleeper
in two places. I have heard that between these sleepers and another
layer of concrete underneath, there is some sort of rubber; I don't
know in what form exactly. And this track makes sounds very much like
Brad's description, except that I would have omitted the word
"rattle".

So do the tracks around Turnham Green *look* any different than on
other parts of the Underground, these days? It's been some years
since I was there.

They are normal LU bullhead rail on wooden sleepers. I'm familiar with the
noise (it's my local station), but I've never regarded it as abnormal. I
think you'll find it occurs at any location in the open with a stretch of
plain line (no points). I can't think of another station where I hear a
similar noise, but that might just be because the other stations where I
wait for trains are either in tunnel or where there are points which would
prevent the sound being transmitted from a distance.
--
Richard J.
(to e-mail me, swap uk and yon in address)

"Richard J." wrote the following in:


They are normal LU bullhead rail on wooden sleepers. I'm familiar
with the noise (it's my local station), but I've never regarded it
as abnormal. I think you'll find it occurs at any location in the
open with a stretch of plain line (no points). I can't think of
another station where I hear a similar noise, but that might just
be because the other stations where I wait for trains are either
in tunnel or where there are points which would prevent the sound
being transmitted from a distance.

I remember hearing a similar noise at Plaistow when I was young. I
don't tend to notice it any more because I'm used to it now, but I'm
sure it still happens.

--
message by Robin May, but you can call me Mr Smith.
Hello. I'm one of those "roaring fascists of the left wing".

Then and than are different words!

I think I used to hear the same noise further along the Picadilly Line at
Northfields.
My guess is that long stretches of track in the open air can develop a 3D
vibration and the noise is a natural harmonic of the length of rail.
The steel is, I guess, less beefy than the heavy rail tracks that don't make
the same sort of noise.
It's a funny boinging, jittering noise isn't it?


"TheOneKEA" wrote in message
om...
I live in Richmond and take the District Line into Central London
about once a week. Sometimes I change trains at Turnham Green to go to
Ealing Broadway. When I am at Turnham Green, I have noticed that the
tracks make strange noises when either a Piccadilly or a District
train is approaching. No matter how fast the incoming train is
traveling, the tracks twang, rattle and vibrate like huge springs are
being snapped back and forth. Once the train has passed by, the sound
continues until the train is well away from the platform.

I have not heard this anywhere else on the Underground except at
Turnham Green and some of the stations east of it (the tracks at Earls
Court and Victoria make the sound, but it's much more faint than at
Turnham Green). Does anyone have a clue as to what I'm hearing?

Brad Chapman

Railgrinder machine has been there, perhaps?

--
regards, Pre38
-------------------------------------------------------------------
See you at the Live London Transport Channel
http://www.centaur.plus.com or on IRC
irc://undernet/uklondontransport

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*
(remove 00 to reply)

"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.