Sound and Communications - February 2008 Issue

Attention to
acoustical
considerations
allows trains to
pass above the
station’s occupants
with a minimum of
disturbance. Note
the videowall
advertising in the
background.
open air-wells and glass ceilings be
similarly utilized. The frequent passing
of both elevated and subterranean
trains added to the potential noise/vibration
characteristics. This was an
acoustical nightmare in the making.
GENEST was charged with the task
of mitigating the noise/vibration concerns
and taming the reverberation
characteristics to a satisfactory level.
ADA was expected to come up with a
design that would provide speech intelligibility
as demanded by prevailing
codes within this 28,821,430-cubic-foot
building, while still being unobtrusive
to the architect’s visual aesthetic.
Vibration Control
In terms of noise/vibration control,
GENEST specified that all rail tracks
be laid in concrete with spring suspension
and be lined with noise-absorbent
materials to mitigate the rumble occasioned
by train movements. Wall construction
would take the form of perforated
metal and concrete with layers
of noise absorption materials installed
behind the perforated walls.
Station platforms, whenever possible,
would be isolated from the main
structure and be shock absorptive to
reduce vibration effects. Those areas
IBA Centralized Communication System Operation
As implemented, the IBA system
operates (in a somewhat simplified
version) as follows:
Note: For the following example,
we will use Hbf; it being understood
that similar conditions apply at all
other stations.
• When a train approaches Hbf,
operators at the IBA Control Center
are notified through an interface with
the railway signaling systems that the
train’s arrival is imminent. This
information is displayed on the
appropriate GUI by the responsible
personnel. Status of the train movement
on a minute-to-minute basis is
essential.
• When the train stops to de-train
passengers, an announcement is
keyed to advise passengers, “Welcome
to Berlin…descend to
level….For information,
consult….Passengers with foreign
passports proceed to….,” etc.
• Waiting passengers are likewise
advised, “The Berlin-Warsaw ICE is
available for boarding on
track….Departure time….The train
will depart in five minutes….”
• In the event of delays or other
unusual circumstances, the operators
at the IBA control center can
override prerecorded messages and
provide timely information and
instructions.
• The system is under constant
supervision, and any equipment
defaults (right down to loudspeaker
line impedance) will appear as a
default on the IBA system’s GUI
consoles.
• Trackside control stations for use
by train operating personnel are
available for communicating with the
IBA operators when unusual circumstances
dictate.
• All functions are logged on
control computers for analysis and/
or response to specific complaints.
At first glance, these sequences
appear fairly uncomplicated, but
multiply this one example by 1100
daily arrivals/departures (one train
every 30 seconds within a 24-hour
time frame), and the need to route
both audible and visual data to 16
track zones and upward of 50 public
space zones, and it becomes rather
complicated.
42 Sound & Communications
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