On Sep 30, 10:20*pm, cj wrote:
On Sep 30, 8:43*pm, The Gardener wrote:





On Sep 30, 8:34*pm, "alexander.keys1"
wrote:

On Sep 30, 4:48*pm, Paul wrote:

On 30/09/2011 10:02, cj wrote:

Arrived at Clapham Junction around 6:30 yesterday evening to be
greeted by a horrendous ear-piercing alarm and the curious sight of
lots of passengers with fingers buried deeply in ears. Most platform
staff were presumably sheltering somewhere from the noise, which
wasn't exactly reassuring to people arriving on trains and who
wouldn't have a clue if the alarm was genuine or not. Once a member of
staff was found the only advice given was to not panic and for
passengers to just cover their ears!

The situation wasn't helped by a failure of the CIS displays, which
temporarily gave up showing actual train departures and instead
instructed commuters to "listen for announcements", which was all but
impossible.

I don't think it was an alarm. *Sounded to me more like the PA system
going haywire (hence no announcements).

--
Paul

Doesn't sound like PA feedback, that's more of a 'hollow' tone due to
the natural reverb of a space shared by mic + speaker, one Youtube
comment says it went on for more than an hour, seems like another case
of "I'm afraid I can't do that, Dave" computer malfunction and
"Computer says no" attitude from the staff, an increasingly common
problem.

Not only that, but clearly no-one with the authority or means to turn
the d**ded thing off! I would not be surprised if none of the station
staff had keys to the electrical switchroom at the station, on some
spurious Elfin Safety argument. I cannot believe that the station
staff would have willingly put up with that sort of noise if they had
the means to do something about it.

According to an apologetic poster at Clapham Junction this evening,
the racket was apparently caused by a power surge to the fire alarm
circuitry. (In my experience power surges tend to permanently fry
electrical things, not render them permanently stuck on "loud", but
then I'm not an electrician, and happy to be corrected...)
~cj- Hide quoted text -

- Show quoted text -

IME, fire alarms are often triggered by the EMP from nearby lightning
strikes.