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Permissive Signalling System

Issue number: RO-2014-016-SI-01
Who it affects: Rail Operators on Melbourne Metropolitan Rail Network
Issue owner: Metro Trains Melbourne
Operation affected: Rail: Other
Background: Investigation Report RO-2014-016
Date: 06 July 2016

Safety issue description

The rules pertaining to passing a permissive signal at stop, place sole reliance on the train driver to provide separation between trains by line-of-sight observation. In the absence of any additional risk mitigation measures, this administrative control provides the least effective defence against human error or violations.

Proactive Action

Action organisation: Metro Trains Melbourne
Date: 06 July 2016
Action status: Released

MTM issued a Weekly Operational Notice on 28 July 2015 stating that the existing details contained in Section 3, Rule 1 of the Book of Operating Rules and Procedures 1994 are to be deleted and the attached details in Annex 6 incorporating an automated voicemail facility is inserted. The voicemail facility includes a recorded recitation of the Rule. Annex 6 requires train drivers to call a telephone number and record a message advising that they are at an automatic signal at Stop and will be proceeding past the signal in accordance with the requirements of Section 3 Rule 1 of the Book of Operating Rules and Procedures 1994.

ATSB response:

The ATSB accepts that the voicemail facility acts as a means of alerting train drivers to the operational rules governing permissive working. However, the ATSB is not satisfied that this process sufficiently mitigates the risk of a similar accident. Accordingly, the ATSB issues the following Safety Recommendation:

Recommendation

Action organisation: Metro Trains Melbourne
Action number: RO-2014-016-SR-38
Date: 06 July 2016
Action status: Released

The ATSB recommends that Metro Trains Melbourne consider additional risk mitigation measures to maintain train separation where the safeworking system allows permissive working.

Correspondence

Date received: 02 November 2016
Response from: Metro Trains Melbourne
Action status: Released
Response text:

MTM Response to Recommendation RO-2014-016-SR-038
1. MTM agrees with this action.
2. MTM refers to and repeats the proactive safety actions already taken by MTM since the incident, as acknowledged in the Report.

3. In addition:
a) MTM has been pursuing a rulebook re-write and has obtained agreement from PTV and all large infrastructure managers who use the same/similar rulebook. The rulebook re-write will have specific focus on reviewing degraded mode operations. This will include consideration of the application of Rule 1 – Section 3.
b) MTM is continuing to apply the Train Protection Warning System (TPWS) in areas of the network utilised by V/Line and removal of dark territory on a riskbased approach progressively as projects are being delivered. A proposal to apply the TPWS to additional signals identified as a risk across the network (i.e. signals not already covered by projects) has been submitted to PTV for funding and approval. Regarding Train Protection Warning System (TPWS) whilst it is acknowledged that the application of TPWS will not enforce compliance with Rule 1 – Section 3, the facility does provide an ‘electronic’ train stop facility for the V/line TPWS fitted fleet.
c) In the interim, risk relating to Dark Territory continues to be managed in accordance with MTM's Enterprise Risk Management procedure. In addition to managing risks associated with Dark Territories, MTM is working with PTV to determine funding requirements and priority. The removal of dark territory, in conjunction with a re-write of the rulebook (as per above), will further support the management of degraded mode scenarios, including management of automatic signal failures which have a direct relationship to Rule 1 Section 3.

   
Current issue status: Safety action pending
Status justification:

The ATSB is not convinced that the proposed actions are sufficient to prevent a recurrence of this type of accident. Until further information is provided by MTM that satisfies the ATSB that the safety issue is adequately addressed, the ATSB will retain the status of this safety issue as ‘pending’

 
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Last update 18 November 2016