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What happened

During June and July 2013, three separate safeworking breaches occurred on the Sydney Trains Network in NSW involving the application of Network Rule NWT 308 (Absolute Signal Blocking) and Network Procedure NPR 703 (Using Absolute Signal Blocking). The incidents occurred at Blackheath on 13 June 2013, Newcastle on 13 July 2013 and Wollstonecraft on 17 July 2013.

In each case, trains were being excluded from worksites, as part of worksite protection arrangements, using the Absolute Signal Blocking (ASB) rule and procedure. The rule and procedure were not adhered to during the authorisation of the ASB resulting in trains entering or passing through the worksites from which they should have been excluded.

What the ATSB found

The three incidents were the result of the requirements of the Network Rule and Procedure not being complied with; particularly full train-in-section checks were not being conducted or the location of worksites was not clearly identified. Also, the Sydney Trains’ systems used to monitor the application of ASB were not consolidated. Instead, the systems made a very limited number of isolated and generally non-safety related findings without identification of how the findings or proposed corrective actions were to be recorded, analysed or implemented.

What's been done as a result

Immediately after the third incident, Sydney Trains suspended use of the ASB rule and procedure for some categories of track work. The suspension was conditionally lifted on 23 July 2014 with some additional procedural requirements and an emphasis on complying with existing requirements for clear communications.

In September 2014, Sydney Trains commenced a trial of a ‘Coded Authorisation Process for Absolute Signal Blocking’. The trial seeks to address the common types of errors identified in ASB incidents by testing a ‘job aid’ which requires improved train-in-section checks, improved identification of work site locations and consistency in the implementation process between the Signaller and the PO for any ASB request. It also requires that a unique code number be issued to the Protection Officer by the Signaller upon any request for ASB. Work cannot commence on track without this code and the code is surrendered back to the Signaller when the ASB is fulfilled.

On the matter of the monitoring and assurance, the ATSB has recommended that Sydney Trains undertake further work to improve its focus on the potential issues involving ASB and its continued safety.

Safety message

ASB is one of five methods of worksite protection which are designed to provide workers with safe track access. It is paramount that track access using any of the methods is properly planned with adequate defence(s) against error, has the Network Rules and Procedures applied consistently and is constantly monitored for compliance.

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The occurrences


Safety analysis


Safety issues and actions

Sources and submissions


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Safety issues

RO-2013-018-SI-01 - RO-2013-018-SI-02 - RO-2013-018-SI-03 - RO-2013-018-SI-04 - RO-2013-018-SI-05 -  

Insufficient guidance in Absolute Signal Blocking

Rule NWT 308 Absolute Signal Blocking and procedure NPR703 Using Absolute Signal Blocking did not provide any guidance on acceptable methods for determining the location of rail traffic in the section or confirming the clearance of rail traffic past a proposed work location.

Safety issue details
Issue number:RO-2013-018-SI-01
Who it affects:All rail operators
Status:Adequately addressed


No forms or checklists

There were no forms or checklists to provide practical guidance for completing the steps required to implement Absolute Signal Blocking (ASB) or to provide an auditable record of the process.

Safety issue details
Issue number:RO-2013-018-SI-02
Who it affects:All rail operators
Status:Adequately addressed


Differences in identifying trains

Differences exist in the way signallers and Protection Officers (POs) identify trains to each other.

Safety issue details
Issue number:RO-2013-018-SI-03
Who it affects:All rail operators
Status:Adequately addressed


Infrastructure not marked on ATRICS screen

Not all major infrastructure was marked on the ATRICS screens for the North Shore panel.

Safety issue details
Issue number:RO-2013-018-SI-04
Who it affects:All rail operators
Status:Adequately addressed


Auditing not effective

The Sydney Trains regime for auditing worksite protection arrangements was not effective in identifying emerging trends or safety critical issues when using Absolute Signal Blocking (ASB).

Safety issue details
Issue number:RO-2013-018-SI-05
Who it affects:All rail operators
Status:Adequately addressed

General details
Date: 13 June 2013 Investigation status: Completed 
Time: 0848 EST  
Location   (show map):Blackheath, Newcastle and Wollstonecraft Investigation type: Occurrence Investigation 
State: New South Wales Occurrence type: Safe Working Irregularity/Breach 
Release date: 02 March 2015  
Report status: Final Occurrence category: Incident 
Anticipated completion: 1st Quarter 2015 Highest injury level: None 
Train 1 details
Train operator: CityRail (now NSW TrainLink) 
Train registration: W521 
Type of operation: Passenger 
Damage to train: Nil 
Departure point:Central Station, Sydney, NSW
Destination:Mount Victoria, NSW
Train 2 details
Train operator: NSW TrainLink 
Train registration: V712 
Type of operation: Passenger 
Damage to train: Nil 
Departure point:Telarah, NSW
Destination:Newcastle, NSW
Train 3 details
Train registration: 117-H 
Type of operation: Passenger 
Damage to train: Nil 
Departure point:Sydney Central Station, NSW
Destination:Hornsby, NSW
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Last update 22 October 2015