The concern related to false information being entered on the brake retention certificates by employees when management are aware that the brakes on the wagons will release if the wagon becomes detached.
The reporter expressed a safety concern regarding incorrect information contained on brake certificates held on trains after brake retention tests have been performed. The reporter stated that train crews are being forced to indicate on the brake certificate that the brakes will hold on the last three wagons even though the operator’s management are aware that the brakes will release if the last wagon becomes detached.
The reporter is concerned that the operator’s management is not allowing for a draw-gear failure between the last two wagons. If this was to occur, the last wagon will uncouple resulting in a runaway. The reporter stated that if a loaded coal wagon weighing 120 tonnes was to runaway on any of the hills on the mainline, it could collide with a following freight train or, even worse, a passenger train, which could result in many fatalities among innocent paying passengers.
The reporter is worried that as the company grows the risk will increase and as the equipment ages it is more likely to fail.
For avoidance of doubt, the reporter's concern relates only to the last two wagons in any consist. Please find below our response to the two questions raised by your Office.
We have operated tandem pair wagon arrangements for a number of years. Tandem pair wagons for registration purposes are treated as two units, coupled together with a solid drawbar.
In some configurations the pair share a braking platform because as a unit, their separation is not envisaged during routine operation. The resulting arrangement does have a potential identified risk. If the solid drawbar failed, then potentially the wagons (as single units) can be subject to brake cylinder leakage and ultimately result in an uncontrolled, un-braked runaway wagon situation, if marshalled at the end of a train.
A risk assessment was conducted with a range of engineering and operations staff, including train crew, to review the wagon arrangement for the identified services. The existing controls were identified as being:
- The lowest in train forces are at this location of a consist (ie the end of the train);
- Design -Structural integrity of wagon: The drawbar components allow the tandem pair to be considered as a single wagon with the weakest structural link being the adjacent knuckle at the end of the tandem set;
- Established operating regimes; and
- Established maintenance regimes.
The risk assessment concluded, as a result of the identified existing controls (both engineered and administrative), that the likelihood of occurrence was very low (Score 1 (lowest) equating to: may occur but only in exceptional circumstances, it would be highly unexpected - Expected Frequency: not in the next 50 years).
The risk assessment recognised that the potential consequences of an uncontrolled wagon movement were significant but, when considered in combination with the extremely low likelihood
of occurrence, concluded that no additional treatment consideration is deemed necessary. In our experience of operating tandem pair wagons across Australia for over 30 years, we have no recorded incidence of a tandem pair wagon solid draw bar failure in this location of a train consist.
The brake retention test represents standard procedure to verify brakes are operational through the train. It is not a test that is related to the issue of potential draw bar failure.
The issue raised by the report concerning incorrect information on the brake certificate may be technically correct. However, the brake certificate is designed to indicate that the braking system is operational and complies with the required retention and continuity tests - which the raked wagons would still do (i.e. not allowing for breakaway).
The reporter's comment regarding the operator not allowing for a solid drawbar failure and the consequence of such failure is reasonable. The reporter's concerns that as the company grows the risk will increase and as the equipment ages it is more likely to fail is again reasonable.
The operator’s response acknowledges and recognises the risk. However, the response seems to indicate that they do not acknowledge or identify other possible failure paths within the solid drawbar assembly, such as the yoke. They furthermore assessed the occurrence likelihood as being very low (1 in 50 years event). The risk assessment seems to not have been informed by knowledge of solid drawbar failures in the past. The ONRSR is aware of at least one recent failure.
The ONRSR considers the reported concerns as being of relevance to all operators who operate this type of wagon configuration. We therefore intend to write to rolling stock operators, requesting them to revisit their risk assessments, particularly, in regards to the hazards pertinent to train partings and runaways, in order to demonstrate the risks associated with these hazards are being managed to a So Far As Is Reasonably Possible (SFAIRP) level.
This letter is in furtherance to our response dated 15 August 2013.
The reported safety concern equally applies to other rail transport operators using permanently coupled wagons with shared braking platforms. The ONRSR has written to freight operators advising of this specific risk.
Not all operators were aware of this issue. The initial response we received from some operators warranted a further request to operators to demonstrate the risks to safety associated with this issue have been controlled So Far As Is Reasonably Practicable.
As a result, further risk controls have either been implemented or are under investigation and the ONRSR has released safety bulletin 4.
ONRSR Safety Bulletin 4 - Preventing unbraked runaways of permanently coupled wagons with shared braking platforms