Great Western Coffee Shop

Yesterday evening, I heard an unusual sound at City Thameslink.
It was a very low pitched tone or hooting, a little like the fog horn of a large ship.
Sounded repeatedly, at least a dozen times, each time for about 20 seconds.
The intervals between it sounding seemed random, but fairly short, less than about a minute I think.

There is a traction substation fairly near, but it did not sound like the hum from a large transformer, which I would also expect to be continous.
It was of a lower pitch than the hum from a transformer, and probably close to the lower limit of human hearing.

I do not recall hearing it before at City Thameslink, or indeed elswhere in London.


Any ideas ?

I don't know how far City Thamelink is from the Houses of Parliament, but my first thought on reading your post was that it was the sound of MPs snoring............ :D

There's a similar noise at Padding in the lawn. I wondered if it was one of those animal pest repellent devices which emits a noise outside of (most) people's hearing range.

Pigeon Repellent possibly? Those things make an awful racket 

On the subject of those. There is the opposite version called a Mosquito which emits a very high pitched noise which is meant to deter failed youff experiments from being able to stand anywhere near the things; an attempt to prevent antisocial behaviour.

I'm probably too old for it to have any effect on me now. But 5 - 10 years ago they didn't bother me then, they still don't bother me now. I knew why they were there too which made me even more determined to stand next to them to "prove a point" (I was young, rebellious, foolish and was and still am no angel... I'm sorry!)

In the past I sent an e-mail to Wiltshire Council to report a sound consistent with an electrical fault (A very high pitched noise) nearly 6 years ago. It turned out it was one of these things in operation on the Public Toilets in Bradford-on-Avon Station Car Park...

I used to walk past one near the entrance to Morrisions in Taunton twice daily as well on the way to the Railway Station (From East Reach side of the town it was the quickest way). That was following a Public Footpath/Right of Way so it shouldn't have been allowed to be used there in the first place!

See also another topic on the Coffee Shop forum, at http://www.firstgreatwestern.info/coffeeshop/index.php?topic=5949.0  ;)

There are no traction substations in City Thameslink station, there are 2 substations that feed the station that are feed from the Cannon St S/S 11kV system, the nearest traction substation is Ludgate Cellars which between Blackfriars and City Thameslink the only loud alarm this has is the fire alarm which is  conventional yodel sounders

I was wondering whether it would be some construction process - maybe drilling into concrete, or vibrating piles into the ground, something like that. Low-frequency sounds carry a long way through the ground, so often that's the only part of the sound you hear. Filtering out the higher frequencies will alter the sound compared with hearing the same thing  through the air.

"Youth repellent" normally takes the form of classical music. It's used at Euston Square tube station - and in the loos by Pershore Abbey.

To give said yoof some credit though, many started recording the sound and using it as their ringtones, so the teachers couldn't hear the phones ringing in class! Credit where credit is due, that was quite ingenious :)

Handel's Water Music, presumably? :P

::) ;D

On that subject, the public loos in Frome and surrounding towns also play classical music as well as talk to you... :o >:( Some nonsense about an alarm going off if you stay in there for longer than 15 minutes :o

Someone else said [as well] that it was to prevent youffs from wanting to be in them... Clearly whoever thought of that has clearly overlooked the concept of headphones... Or that fact that some youff might like classical music ;D

Of course you run the risk of the alarm going off if you forget to remove your headphones and don't hear the warning.......... :-[


I wholeheartedly agree. I am sure I have put on the forum in the past I was no angel as a teenager... Could I say I did this also when I was young...? Perhaps I shouldn't... But I couldn't deny it either ;)

You mean you are an angel now?   ;D ;D

I couldn't possibly comment ;D