Digital shields

KiwiRail is pioneering the use of digital shields as part of work in and around the rail corridor. Digital shields help protect rail workers and infrastructure, while reducing the impact on passengers as works are being carried out.

This industry-leading technology was developed during KiwiRail’s Trentham to Upper Hutt double-tracking project in the Wellington Region. The shields have been used to protect excavator drivers from overhead power lines and other sensitive areas such as the live rail corridor, by locking the controls of excavators if any part of the machine gets too close.

Digital shields 1

The shields are made by creating a virtual twin of the physical environment, using a laser scanner. This survey technique collects millions of points of data, which are then used to build a 3D digital model.  These models allow us to create digital shields a set distance from the position of the real-world objects.

Once a shield is created, it is sent to a computer onboard the excavator that is linked to a GPS unit.  The system on the excavator knows where the machine is, and through a series of sensors, what shape it is, as well as where the shield sits.

If the excavator comes into contact with the location of the digital shield, then a signal is sent to the hydraulic system and the controls are locked out, preventing the machine from coming too close to the real-world hazard.

Digital shields 2

The technology used to create the shield used on the Trentham to Upper Hutt line can be fitted to most modern excavators, and differs from other systems as it is a truly 3D protection system (as opposed to geofencing or slew locks and height restrictors). 

It can be applied to underground pipes and cables, as well as above ground items.  Alternatively, it can be used to protect newly constructed items, avoiding accidental damage and rework.

KiwiRail is scoping opportunities to use the shields in other locations where works are being carried out, including in Auckland.

Find out more about these digital shields by following these links:

Digital shields on the railway - YouTube

KiwiRail visits Trentham School - YouTube

Double-tracking Trentham to Upper Hutt - YouTube

Digital shielding enables rail repairs without service stoppage | BIM+ (

Digital shields protecting workers and trains near Wellington - EPIC Work NZ


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