An aerial view of a railway line snaking through a lush green corridor, with an exposed, reinforced slope on one side indicating recent stabilisation work. The contrast between the natural bushland and the engineering intervention highlights the ongoing efforts to protect the rail infrastructure against the backdrop of a scenic coastal area with a cargo ship in the distance.

Johnsonville Line Rockfall Mitigation

The Johnsonville line cuts up through the Ngaio gorge through 5 tunnels. Over the past 15 years, Abseil Access has helped Kiwirail reduce rockfall on various sections of the line and over the tunnel portals.

In 2019 AA conducted the 6th such project, installing active mesh and anchors between tunnels 1 & 2. The netting was installed first to reduce the chances of rockfall during the drilling phase. The team then use an A-frame drill rig to drill and install 32mm and 25mm diameter GRP anchors.

A close-up view of a KiwiRail train locomotive on a track adjacent to a forested hillside where rockfall mitigation equipment is set up. Overhead booms and safety ropes are visible against a backdrop of dense green foliage, with the bright train lights shining in a misty environment, highlighting the integration of rail transport and environmental conservation efforts.

The work included:

  • De-vege and rock scaling on specific line closure days
  • Working with Aurecon to design a constructible solution
  • Drilling 75mm holes and installation of 32mm and 25mm diameter glass reinforced plastic (GRP) anchors using a cliff face A-frame drill rig.
  • Installation of Geofabrics double twist PVC coated mesh.
  • Working under an active rail line with safety stop boards and rail protection.

All access was established from the top of the site reducing the need for hi-rail vehicles and rail closures. GRP bars reduced the electrical hazard risk around the high voltage catenary as well as eliminating corrosion issues. The netting was installed first to reduce the chances of rockfall during the drilling phase.

Contact Us

An aerial view of a railway line snaking through a lush green corridor, with an exposed, reinforced slope on one side indicating recent stabilisation work. The contrast between the natural bushland and the engineering intervention highlights the ongoing efforts to protect the rail infrastructure against the backdrop of a scenic coastal area with a cargo ship in the distance.
A close-up view of a KiwiRail train locomotive on a track adjacent to a forested hillside where rockfall mitigation equipment is set up. Overhead booms and safety ropes are visible against a backdrop of dense green foliage, with the bright train lights shining in a misty environment, highlighting the integration of rail transport and environmental conservation efforts.
Image of the Johnsonville Line Rockfall Mitigation Project
An overhead view of a railway line running at the foot of a slope partially covered with rockfall netting illustrates the measures taken to protect this vital transport infrastructure. The netting is a patchwork of protection amidst lush greenery, showing a proactive approach to reducing natural hazards in a wooded area.
DCIM100MEDIADJI_0032.JPG
An aerial view of a steep slope where a team of workers in safety gear is installing rockfall mesh. Amidst scattered vegetation, the slope reveals the ongoing construction with a crisscross of ropes and partially laid mesh, symbolising the intricate work of ensuring slope stability and preventing soil erosion in a natural setting.
Technicians in orange overalls wearing harnesses carefully navigate a sparse, sloping terrain with geotextile covering dotted with soil nails and anchor plates. They are attached to yellow safety ropes, highlighting the precision required in their movements while conducting geotechnical stabilisation to protect the landscape from erosion.
A close-up view of a KiwiRail train locomotive on a track adjacent to a forested hillside where rockfall mitigation equipment is set up. Overhead booms and safety ropes are visible against a backdrop of dense green foliage, with the bright train lights shining in a misty environment, highlighting the integration of rail transport and environmental conservation efforts.loading=
An overhead view of a railway line running at the foot of a slope partially covered with rockfall netting illustrates the measures taken to protect this vital transport infrastructure. The netting is a patchwork of protection amidst lush greenery, showing a proactive approach to reducing natural hazards in a wooded area.loading=
An aerial view of a steep slope where a team of workers in safety gear is installing rockfall mesh. Amidst scattered vegetation, the slope reveals the ongoing construction with a crisscross of ropes and partially laid mesh, symbolising the intricate work of ensuring slope stability and preventing soil erosion in a natural setting.loading=
Technicians in orange overalls wearing harnesses carefully navigate a sparse, sloping terrain with geotextile covering dotted with soil nails and anchor plates. They are attached to yellow safety ropes, highlighting the precision required in their movements while conducting geotechnical stabilisation to protect the landscape from erosion.loading=
Download the PDF
PDF 763.0 KB