Real-time monitoring online
Eyes on potential slips along rail line as new system goes live
A real-time monitoring system that keeps watch for potential slips on the slope beneath the Kā piti rail line has gone online.
Commuters using the 25kilometre-long section, which runs on steep hills overlooking the coast, have been disrupted after multiple slips in recent years.
Instrumentation experts from design and engineering firm WSP installed monitoring equipment at 20 sites along a section of the North Island main trunk link between Paekā kā riki and Plimmerton stations over the past 18 months.
The new system, which includes slope movement and debris sensors, rain gauges, soil moisture metres and nightvision cameras have an alert threshold. KiwiRail engineers, train controllers and WSP will be notified if the system picks up any slope or debris movement, and pictures of each site are taken every 15 minutes.
If its sensor threshold is triggered, site photographs are taken every minute.
In August 2021, a slip just south of Paekākāriki derailed two commuter carriages after a night of heavy rain, and a year later State Highway 59 was closed for nearly a month after a large slip blocked the road.
KiwiRail also slapped a 40kph speed restriction on the section after multiple slips last year.
WSP’s principal instrumentation engineer Mike Lusby said while the monitoring system couldn’t prevent landslips, it could keep trains and passengers safe if they happen.
‘‘It does give KiwiRail warning in real-time, so trains won’t plough into fresh slips, derail and put people’s safety at risk,’’ he said.
KiwiRail’s performance manager Shaun Bullard said realtime monitoring of the slopes was ‘‘crucial’’ because slips could cause significant damage and lead to safety issues, delays and costly repairs.
‘‘By constantly monitoring the ground conditions of the line, we can detect any changes promptly and take corrective measures before severe damage occurs,’’ he said. ‘‘As extreme weather conditions, triggered by climate change, become more frequent, this kind of real-time monitoring lets us respond quickly and proactively to minimise the impact of these events on our rail infrastructure.’’
A similar monitoring system will also be installed at a section of the Johnsonville line.