Funding for replacement traction poles a big win for Wellington rail commuters

  • Published Date 25 May 2017

Nearly $100 million has been allocated to Greater Wellington Regional Council and KiwiRail to replace 1274 wooden traction poles which, without replacement, would lead to significant service disruption on Wellington's Metro Line Network.

Today's budget announcement of $98.4 million in funding will enable the replacement of all timber poles in the network and renewal of overhead lines at the same time, within four years.

The poles support the overhead wires which deliver power to the trains.

"This is great news for the region's train users," says Cllr Barbara Donaldson, chair of Greater Wellington Regional Council's Regional Transport Committee. "It means there will be no service disruptions as the poles deteriorate, instead there will be a proactive and comprehensive replacement programme.

"It is a big win for the region's rail network and another step in raising the quality of our services to the public.

"Funding pole replacement is essential for safe operation on the rail network. Without it we could have faced the prospect of having to close routes within four years as they continue to deteriorate. This investment is vital for the resilience of our regional rail network and will also improve day-to-day reliability."

KiwiRail chief executive Peter Reidy says the Wellington funding is a welcome acknowledgment of the importance of rail in New Zealand. "Our infrastructure teams work incredibly hard to keep the system running smoothly but today's announcement will allow the completion of a major upgrade of the Capital's network. There's a lot of work ahead, but our people are excited about the challenge."

Planning and procurement will now begin to ensure the last of the poles are replaced before they fail.

Background on timber traction pole replacement

  • In establishing the Metropolitan Rail Operating Model in 2011 the Crown retained ownership of the traction poles on the Wellington rail network.
  •  While Crown investment has funded the replacement of a number of the wooden traction poles, many remain and are at the end of their life meaning safe and reliable performance cannot be guaranteed. The timber traction poles are coming to the end of their life increasing the risk of failure and serious safety incidents.
  • The absence of a funded programme to replace the timber poles is likely to require the closure of all Wellington Metro Rail Network routes equipped with these poles by 2021, or earlier.
  • While the great majority of affected poles are located on the Upper Hutt and Melling routes, all Wellington Metro Rail Network electrified lines still utilise timber traction poles.
  • KiwiRail is using best practice inspection techniques and individual pole replacement to control the safety risk resulting from catastrophic pole failure and minimise service disruption resulting from unexpected failure. However, there are limits to the effectiveness of this approach:

The inspection techniques are not reliable enough to detect all poles before they fail. As the number of poles approaching failure increases, the chances of an undetected failure also increases

The risk of undetected pole failures presents a significant safety risk to rail passengers, the public and railway staff. Since 2007 there have been 13 incidents where deteriorated poles has been undetected and poles have failed in service. The worst incidents have involved trains colliding with the failed traction poles.

The rate at which poles require replacement will increase to the point that ad hoc replacement becomes unmanageable; disruptive, inefficient and expensive.

  • Failures of the traction system can cause significant disruption to the travelling public across both rail and road transport modes, as both are required to meet the peak time capacity demands. An economic study into the impacts of the railway between Wellington and Petone being closed for six days due to storm damage indicated the costs to the economy were between $12M and $43M. Severe congestion also resulted on the road network as the only other viable mode of travel was by private vehicle.
  • Based on an assessment of pole condition and the impact of these consequences, KiwiRail and independent technical assessments state that these poles must be replaced in the next 3 to 5 years (completion by 2021 at the latest).

The recommended option was:

Face Renewal (all timber poles in the network replaced and overhead lines renewed at the same time) - which addresses the primary issue, which is to replace the timber traction poles within four years (by 2021) which is an acceptable timeframe. The investment cost for this option is $98.4 million.

Updated April 28, 2022 at 2:55 PM

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