Page 94 - 捷運技術 第35期

86 Jeffrey S. Stover CITYFLO 650 System Overview

support of these functions, the Region ATO is responsible for the generation of various non-vital
train movement controls and commands for the respective elements located on the wayside such as:
˙Ride Comfort Control, e.g. jerk limiting（VATO）

˙Stopping accuracy（VATO）
˙Train operation according to commanded speed profile（acceleration and deceleration）,
including performance levels, e.g. coasting, energy saving etc（VATO）
˙Door Control Requests（RATO and VATO）
˙Onboard triggers for audio announcements and dynamic displays（VATO）
˙Wayside Passenger Announcement triggers to platform display systems（RATO）
System status and control data associated with each Region ATO are processed and sent to the
Central Control System where the current status of the system is displayed.

The Region ATO units are also operationally redundant with a Master and Standby unit. Each
independent primary and backup ATO system operates in conjunction with the Region ATP primary
and backup systems. Both the primary and backup Region ATO collect data from their own region,
but only the primary system issues commands and requests.

To display the proper sign and announcement at each station, the Region ATO monitors the
location of the train as it approaches a station. Once the train has stopped at a station, the Region
ATO monitors the dwell of the train to trigger the relevant station sign and announcement. The
Region ATOs message identifies to the Passenger Information System the specific station sign to be
displayed and the specific announcement to play.

Besides station control, the Region ATO computer is also responsible for reading all the
vehicle tag readers that verify a train’s consist during initialization. Because the transition areas are
distributed throughout the system, an RS-485 serial network or Ethernet is used to connect the
Region ATO to the vehicle tag readers. When a particular transition area becomes activated and
after verifying the data received from the vehicle tag readers, the Region ATO passes the train
initialization information to the Region ATP. The Region ATP communicates with the Vehicle ATP
to complete the initialization process.

The Region ATO interfaces with the Region ATP computer via the Wayside Network. It also
sends and receives vehicle messages from the Vehicle ATO through the Region ATP.
The Region ATO interfaces with the Central Control System via the Wayside Network

2.3.3 Train to Wayside（TWC）Communications System
Communication between the trains and wayside for train control is provided by the Train to
Wayside Communications（TWC）subsystem. The TWC is a radio frequency（RF）subsystem that
uses a Spread Spectrum Code Division Multiple Access（CDMA）modulation technique at 2.4 GHz.
The RF communications uses either a leaky coaxial cable or Line of Sight（LOS）antenna network
along the wayside that transmits data to the trains via their onboard mobile antennas.
The trains and regions communicate through the TWC “link” every COMM Cycle. The
trainborne ATC continuously receives messages from the wayside ATC as long as the
communication link is maintained. When a train loses communications, the wayside ATC creates
a protection block around the lost-communication train and, at the same time, the trainborne ATC
equipment applies the service brakes. Upon restoring the communication, the wayside ATC
removes the blocks associated with losing communication with that train.