GIH was responsible for the metrological monitoring of a very unusual test conducted by Deutsche Bahn - a track warping test. A previously selected rail area was heated to a very high temperature, which initially caused the rail to deform and then warp. This track warping test took place in June 2017 in southern Lower Saxony. During the test four Zoller+Fröhlich 5006/5010 laser scanners mounted on their sides, were operated in profile mode for the entire duration of the test. They were used to record the rails over the entire length of the approx. 9 m long fault area. During the test the positions and orientations of the four laser scanners in the room were determined and continuously monitored, using total station measurements with three prisms mounted on each scanner.

The evaluation of the individual point lines over the epochs, was realised via the estimation of B-splines and finally presented in a video. In addition, 42 corner cube reflectors were installed in 17 profiles, which were measured with the Leica AT906-LR laser tracker during the test. Static 3D point clouds were also taken with a Zoller+Fröhlich Imager 5010 laser scanner before the start of the test, immediately after the fault and some time after the fault. The position of the rail before the start of the test (top), shortly after the fault (centre) and after cooling (bottom) is shown in the figure.