PTS - Personal Track Safety Safety Critical Communications Flashcards

What is a 'three-part communication' and why is it used for safety-critical messages on the railway?

Answer: A protocol where the sender states the message, the receiver reads it back, and the sender confirms it is correct — ensuring the message is accurately received

Three-part communication (challenge, readback, confirmation) ensures that safety-critical messages are accurately received and understood, reducing errors that could cause accidents.

What should a COSS do if they are uncertain that a verbal message from the signaller has been fully understood?

Answer: Request the signaller to repeat the message and use three-part communication to confirm accuracy

If any doubt exists about a received message, the COSS must ask for it to be repeated and use three-part communication to verify accuracy before acting on it.

What is the purpose of using standard railway terminology in safety-critical communications?

Answer: Standard terminology ensures unambiguous communication by using precise, universally understood terms that reduce the risk of misinterpretation

Standard railway terminology provides precise, unambiguous language understood by all trained personnel, eliminating misinterpretations that could cause accidents.

When is radio communication preferred over mobile phone for safety-critical messages on Network Rail infrastructure?

Answer: Network Rail Integrated Electronic Control Centre (IECC) radios or GSM-R are preferred as they provide direct, reliable communication with signallers in real time without network congestion issues

GSM-R (Global System for Mobile Communications — Railway) or IECC radio provides dedicated, prioritised communication with signallers that is more reliable and secure than standard mobile networks for safety-critical use.

What action must be taken if a COSS's radio fails during an active line blockage?

Answer: Suspend all work within the safe working limits immediately, ensure workers are in a position of safety, and attempt to re-establish communication — work may not resume until communication with the signaller is restored

Radio failure during an active line blockage means the COSS cannot confirm the blockage status — all work must stop and workers must be withdrawn until communication is restored.

What is the correct response of a COSS when the signaller says 'your line blockage is no longer in place'?

Answer: Immediately withdraw all workers to a position of safety and confirm they are clear before acknowledging to the signaller

If the signaller cancels a line blockage, the COSS must immediately withdraw all workers to a position of safety before anything else — trains could be authorised into the section at any moment.