Concern regarding the breakdown of communication between network controllers
The reporter has raised a safety concern regarding a breakdown in communication between network controllers on approach to [Location 1], which had the potential to result in a train entering an occupied section under clear signal indications.
The reporter states that [train number] was presented with signals indicating a clear, unoccupied section of track from [Location 1] to [Location 2]. On approach to [Location 1], the train crew received a ‘reduce to medium with a 65 kph’ indication, followed by a ‘clear medium speed 65 kph’ on signal [A]. Signal [B] was also displaying clear medium speed 65 kph.
The reporter states that signal [C] also had a clear normal speed indication, which informs the crew that the next signal, [D] - starter signal is at proceed. Signal [C] should display a 'normal speed warning' when starter signal [D] is displaying ‘danger/stop’. The reporter did not recall being contacted by network control to advise that the line ahead was clear.
The train crew were then contacted by network control and advised of an incorrect signal aspect and to stop the train. The train stopped as instructed, and prior to moving towards the starter signal [D], the crew contacted network control to gain permission to move the train towards the starter signal, and at this point they were informed that they had a clear section.
The reporter states that while the train stopped well short of starter signal [D] by approximately 2,500–2,800 meters without incident, there was a breakdown in process (or communication) between the two network controllers that resulted in a train being signalled into an occupied section.
[Operator] takes these matters very seriously, and we strive to improve our safety critical communications immediately. In relation to the specifics of the REPCON we can advise that after receiving this REPCON, we elected to undertake a further review using the additional information which has resulted in the following learnings:
- Initial information provided at the time of the error was a simple human error with selecting wrong route, however the additional information provided from the REPCON indicates otherwise.
- Our initial response could have been much better, to determine the severity of the occurrence, although there was no immediate risk.
- A Safety Bulletin is in the process of being issued to highlight and reiterate the procedures in regards to signal [number].
- An engineering change will be implemented in the next six months (this was in the plan already) to alleviate any further administrative control of holding signal [number] at stop.
Further to above point, we’ll engage with the project to determine if these works can be brought forward.