Unstable Remutaka train track could be cut anytime: KiwiRail

KiwiRail has identified an area of loose and unstable material under its Remutaka Hill train track which could slip and undermine the track, taking it out of use for at least several weeks.

The area of what the company calls “localised instability” is 1.4 kilometers north of the Remutaka Tunnel _ Wairarapa side _ and just below the rail line on the embankment. 

Modelling of the land under the line shows there is a “medium-to-high risk” of a slip occurring.

“The shoulder or space between the rail line and the embankment could potentially undermine the  railway track,” KiwiRail told The Star in an explanatory note. 

In 2020 the risks facing the area were described as “critical/catastrophic,” but KiwiRail said that assessment was the potential impact on its service delivery _ “not risk to life or public safety.”

A KiwiRail spokesman added that “in this case the level of risk of an event happening is medium to high, and the consequences of the risk occurring are assessed as “critical/catastrophic” for the rail service. 

If a slip happens, “the track could be undermined and potentially closed for a number of weeks, preventing rail services from running.” 

KiwiRail said it had already completed design work for installing metal shear lock piles which will be “driven into the ground in a grid pattern” to stabilise the whole unstable area.

It noted that Wellington’s topography means there is a “level of inherent risk” in some areas _ including the Plimmerton to Paekakariki section of the main trunk line and the Ngaio Gorge section of the Johnsonville line.

Greater Wellington Regional Council released a report in December highlighting a $1 billion backlog of chronic underinvestment and significant backlogs in maintenance programmes across the region’s rail network, “which threaten to bring passenger rail services to a halt if not addressed.”

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