Together with AFRY GEO, AFRY Norway took on five railway tunnels in Dovre. The team needed detailed point cloud data to determine whether there was enough space for frost and water protection at critical points. Using NavVis VLX, and occasionally a headlamp, they captured thousands of meters of railway infrastructure, navigating steep, unlit tunnels within the available windows between passing trains.
Andreas Aschehaug, BIM Strategist at AFRY Norway, shared how the project came together, what kept the team moving, and what he would recommend to others taking on similar work.
The assignment, carried out in collaboration with AFRY GEO, covered five tunnels in Dovre: four on the Dovre Line and one on the Rauma Line, just before the descent toward Åndalsnes.
Our task was to deliver detailed point cloud data for AFRY GEO’s further analysis and modeling. The data would help determine how much space was available for frost and water protection at critical points.
The mobility of NavVis VLX reduced the time needed for capture. Cloud-based processing also allowed us to review the results while we were still in the field and determine whether any additional coverage was needed.
The tunnels ranged from 100 to 783 meters in length. The longest was the Grønbogen turning tunnel, just after Dovre station in the direction of Trondheim. With an 18‰ gradient and no lighting, capturing it meant relying on a headlamp and keeping a steady pace between the railway sleepers, which did not quite match my stride.
We were also working within tight windows between passing trains. I wanted to be confident in the result while working safely, so I captured the longest tunnel in two rounds.
Andreas Aschehaug, BIM Strategist at AFRY NORWAY
Using NavVis VLX saved us time and allowed us to leave the site knowing we had captured enough data within the required tolerance. Being able to check the results before leaving gave us confidence that we would not discover any gaps later.
And after walking 3,132 meters through the tunnels, it was good to take a break and enjoy the surrounding scenery!
Back at the hotel in Dombås, we processed the data and confirmed that the capture had delivered the quality we needed, even in these demanding conditions.
The resulting point cloud provided a clear overview of the tunnels and made it possible to assess whether there was sufficient space for frost and water protection at the critical points. AFRY GEO then modeled the proposed protection in Leapfrog.
Take your time. You will still be faster than with a stationary laser scanner.
For AFRY Norway, the project showed that mobile capture can work in demanding railway environments and within tight timeframes. By checking the data before leaving the area, the team could head home with confidence, knowing they had a reliable basis for further analysis and modeling. For infrastructure teams working under similar conditions, the benefits of mobile capture are compounded by the reduced risk of return visits and late surprises.
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