Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 11 Page 208 of 265
IMPORTANT: As Wig-Wag configurations are more complex to create than
intersection configurations it is strongly recommended that they should only be
created by Intersection Engineering at Siemens, Poole.
28.5.2 Flexible activation
Typically Wig-Wags are activated by a button within the fire or ambulance station.
Where just simple button activation is required this may be implemented with a
Puffin Demand unit, using the demand indicator to signal back that the controller
has registered the demand.
Where a more sophisticated control system is required a full activation box is
available. For more information download the Wig-Wag Brochure from the Siemens
Traffic website.
Interfaces to control panels and mimic signals are provided using standard
controller digital inputs and outputs and optionally phase drive outputs.
28.5.3 The Wig-Wag Sequence
For most of the time, the Wig-Wag Signals are extinguished. Only when it is
required to stop the normal traffic flow are the signals illuminated, to let an
ambulance leave the station quickly and safely for example.
The default Wig-Wag sequence consists of a fixed 5 second amber period, followed
by the left / right flashing of the red signals.
 
Figure 35 – Wig-Wag Signal Sequence
When it is clear for the traffic to proceed again, the flashing red signals are
extinguished.
Wig-Wag Signals can also be positioned facing the egress of the fire or ambulance
station to allow the drivers of the emergency vehicles to confirm the state of the
other Wig-Wag signals. Where regulations (such as those in the UK) stipulate that
all vehicles, including emergency service vehicles, must stop at flashing red Wig-