Proven WLANs for Rail Signaling and Infotainment Systems


Carborne ATO Signaling


Redundant roaming to enable efficient ATO service

The role of ATO (Automatic Train Operation) systems is to fulfill basic train operations within the protection limits imposed by ATP systems. With ATO, the train can automatically start and stop at stations, as well as control the doors. To offer frequent train service, dwell times at stations should be kept to a minimum, but swift operations in busy metro stations are always a challenge. ATOs use wireless LANs, and in order to run efficiently, the wireless signals must be reliably handed off between base stations—even when the train is on the move. Equipment redundancy is central to achieving this high level of availability. With an innovative mix of redundant dual RFs and Turbo Roaming technologies, Moxa’s dual RF products offer a redundant roaming path via 2.4 or 5 GHz dual-band operations to overcome any connection loss while a train is approaching a station.

Onboard ATO signaling

Application Requirements

  • Availability
    • Continuous radio link to the train
  • Interference–proof
    • Overcome the interference in train stations' complex RF environments
  • Failure-proof links
    • All ATO systems must be duplicated to avoid link failure
  • Vibration-proof design for robust connections under harsh rail conditions



Moxa's Solutions

  • Redundant ATO network
    • Onboard: two AWK-5232 dual-RF clients are deployed at each end of the train for redundancy
    • Train Station: four AWK-6232 outdoor dual-RF APs are placed at the train station for dynamic connections to an approaching train
  • Redundant millisecond-level Turbo Roaming
    • Combines client-based Turbo Roaming with redundant dual-RF design
  • Interference-proof design
    • One path runs at 802.11b/g and 2.4 GHz, and the other at 802.11a and 5 GHz to avoid RF interference
  • M12 connectors to overcome vibration
  • Certifications
    • Onboard: EN 50121-3-2 and IEC 61373
    • Trackside: EN 50121-1/50121-4