IEEE Characteristics

IEEE Characteristic #1

The primary difference between CBTC and Conventional signalling is the ability of a CBTC system to determine the location of a train independent of track circuits.

IEEE Characteristic #2

The location of the train is transmitted via a high capacity two-way communication medium and radio to the Wayside Unit.

IEEE Characteristic #3

It's not enough to determine the location of a train, it must also be safe.
IEEE 1474.1 defines many safety functions which can be broken down into 4 broad categories:
  • Positioning functions - the ability of a CBTC system to track and keep trains safely separated from each other.
  • Speed determination and monitoring functions - The ability of the CBTC system to determine, monitor and control the speed.
  • Travel direction, routing and interlocking function - when routing a train, the path is dedicated to that train.
  • Miscellaneous Function - work zones, door control and interlocks, broken rail detection and grade crossings.