Overhead powerlines dewirement


Overhead powerlines dewirement

Key points:

  • Unsecured flat rack end wall extended upwards, dewiring high voltage overhead line equipment
  • During emergency response, risk of close proximity of high voltage overhead line equipment to the flat rack end wall was not identified or controlled.
  • Occurrence highlights the importance of ready access to checklists for rarely completed and emergency response tasks, and effective coordination during an emergency response.

Over a kilometre of overheard powerlines were pulled down when the collapsible end wall of a flat rack container being transported on a freight train extended in transit, contacting an overpass and pulling down the high voltage lines, a new ATSB report details.

The incident occurred on 18 August 2018 when Aurizon-operated intermodal freight train YC77, consisting of a single 2800 class diesel-electric locomotive and 32 flat wagons and crewed by a single driver, was approaching Cooroy, in the Sunshine Coast hinterland, en route from the Acacia Ridge Intermodal Terminal in Brisbane.

Examination of CCTV footage showed that as the train passed through Cooroy, the rear end wall of the top of a stack of three empty flat racks was in the extended position, with overhead line equipment (OHLE), including copper wires, entangled on the wagon and dragging along the station platform. No-one was on the Cooroy station platform at the time of the dewirement, although a southbound passenger train was scheduled to arrive about 30 minutes later.

“The ATSB investigation found that securing of the collapsible end walls of the flat racks was not checked on arrival at the freight terminal or after they were loaded on the train,” said ATSB Director Transport Safety Dr Mike Walker.

“In addition, there was not an effective system in place to ensure personnel required to check the securing of unusual loads, such as empty flat racks, had sufficient knowledge of their responsibilities, or ready access to relevant procedures, guidance and checklists.”

Although the OHLE was de-energised due to the tripping of a circuit breaker during the dewirement, it was not considered electrically safe until it had been isolated, tested and earthed. The ATSB found that on multiple occasions following the dewirement, train crew accessed a three metre exclusion zone associated with the OHLE, prior to the wires being isolated and earthed on site.

Further, network control centre personnel did not advise train crew of the status of the OHLE during the emergency response period, and the infrastructure operator, Queensland Rail (QR), did not have an effective process in place to ensure that safety-critical actions were co-ordinated and completed when multiple network control officers were involved in responding to an OHLE emergency, the investigation notes.

“This occurrence has highlighted the importance of having checklists for rarely conducted tasks and emergency response tasks in the rail environment, and ensuring these checklists are readily available and used by operational personnel,” Dr Walker said.

“This includes checklists for loading and securing personnel, rail traffic crew and network controllers.”

In response to the incident, Aurizon has updated its processes and checklists for the loading of flat racks, provided further training on flat rack securing requirements, and is undertaking a program to improve access to its safety management system, including relevant procedures and checklists. In addition, Aurizon is in the process of drafting procedures related to driver only operations (DOO) on its network.

QR has also mandated the use of a network control officer checklist for OHLE emergencies and is reviewing related aspects of its emergency response procedures. In addition, QR has provided additional training to both network control officers and train crew in relation to identifying objects in close proximity to OHLE and applicable exclusion zones. QR has also taken proactive safety action in the form of further training for NCOs when dealing with emergencies involving a DOO crewing arrangement.

You can find here the investigation report RO-2018-011: Dewirement involving freight train YC77, Cooroy, Queensland, on 18 August 2018

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