Capturing one of the worlds longest tunnels

Author: Monica Miller Rodgers, May 2016 

When the Gotthard Base Tunnel officially opens in June 2016 as part of the New Rail Link through the Alps (NRLA), a construction project 20 plus years in the making at 9.8 billion Swiss francs will be one of the world’s longest and deepest railway tunnels. At 57 kilometres long and with a rock overburden of 2,300 metres, the tunnel increases the total transport capacity across the Swiss Alps while reducing passenger travel time between northern and southern Europe by one hour. With minimal gradient and wide curves, the route is also a flatter, lower-level journey at only 550m above sea level. The whole tunnel system measures a total of 152km, plus almost 50km of new built outdoor tracks.

When Grunder Ingenieure AG, a leading Swiss engineering firm specialising in rail surveys and long-time user of Leica Geosystems solutions, was sub-contracted by the Alptransit Gotthard AG, the firm knew it would be a challenging task but one for the history books. One of the main tasks, before the tracks open for the test operation, was to capture all the infrastructure of the tunnel for as-built documentation.

“There are several stakeholders working on the overall project, and we were tasked with registering the entire infrastructure to collect for the infrastructure database of the Swiss Federal Railways. All these users can now access this information,” said Gilbert Roulier, Grunder’s director of Imaging, Laser Scanning and Mobile Mapping. “Entering the underconstruction tunnel and outdoor tracks also presented organising challenges that we needed to account for with our engineers and surveying instruments.”

The firm selected the Leica Pegasus:Two to safely and efficiently capture the entire infrastructure of the newly-built open tracks. In combination with Leica Geosystems total stations, Grunder was able to provide a complete database of 3D imagery and point clouds covering the rails, signage, posts, electrical lines, and further installations and structural elements.

Explore next chapter: On the fast track

Story: Capturing one of the worlds longest tunnels
Chapter 1: Introduction
Chapter 2: On the fast track
Chapter 3: Sensor merging for digital reality