Digital shielding enables rail repairs without service stoppage
10 November 2020
Digital shielding is being used in New Zealand to allow teams and plant to carry out railway construction next to live railway lines with no service stoppages.
Engineers send a shield to the plant’s computer, and via GPS, the plant knows when it’s close to a digital shield; if the plant touches the shield, it shuts down.
This project started when KiwiRail (New Zealand’s state-owned rail operator), contractors Downer and Robertson Battock, Trimble software dealer Sitech NZ and local plant distributor CablePrice wanted to develop a system that would protect people and assets in the rail corridor and provide additional controls when excavators work next to live rail.
Sitech used laser scanning and CAD software for data acquisition and BIM modelling respectively, and a 3D ‘avoidance model’ was created. However, a leap was needed for plant to use the model.
Sitech’s Advanced Solutions Team collaborated with Trimble to extend the capability of Trimble’s Earthworks GNSS machine guidance system, by incorporating another Trimble system, TMC (Trimble Marine Construction).
According to a Sitech spokesman: “On site the solution is a seamless integration of Earthworks and TMC, where the operator has two interfaces driven by one positioning platform. The operator can dig accurately to the design model using Earthworks, and if the machine is moved too close to the avoidance zone, TMC triggers a shutdown of the machine’s controls.
“Furthermore, Trimble’s augmented reality technology has been adopted as part of the QA process. Before the 3D avoidance model is uploaded to the machines, Trimble SiteVision allows the project team to validate that the model covers all of the relevant assets on site.”
Aside from the obvious health and safety benefits, it also means that services on nearby existing railway lines do not have to be stopped.