Test of measurement methods for the safety of railway tracks

Development of a measuring method for deformation measurement / vibration measurement of railway tracks during train crossing

In a master's thesis in the surveying course of studies, a photogrammetric measurement method was developed to measure deformations and vibrations of railway tracks during train passage. The aim is to draw conclusions about the stability of the track bed.

Precision has always been required in the construction of railway tracks, as this is an important component for the safety of rail traffic. Because if "the rails are crooked", "uneven", or move too much, everyone can imagine that this can lead to dangerous vibrations and also derailments. High speeds and the weight of the rail vehicles also increase the demands.

In addition to precise geometric measurement and laying of the railway tracks, the track ballast has an important function: The horizontal and vertical stabilization of the tracks, as well as the absorption and damping of vibrations and weight loads. In track construction, ballast tamping machines provide the necessary and uniform stability of the track bed. However, some areas, such as points, can only be tamped with ballast manually during track construction. This can lead to cavities that cause the track to sink too much under load or to dangerous vibrations during train crossings.

Such weak points in the track ballast are to be identified with photogrammetric surveying methods. As part of Artagnan Falk's master's thesis in the surveying master's course, a new measurement method was investigated to determine both deformations and vibrations during loading/train passage. With different camera systems movements of a few millimeters could be measured during the passage of different train loads (ICE, IC, freight train). From these measured values, conclusions can be drawn about the stability of the track bed and countermeasures can be taken.

The video shows the passage of an ICE over the observed switch area. In the video, the view of one of the measurement cameras is also embedded together with the graphical representation of the deformations/vibrations. The measured deformations/vibrations are shown here by means of a graphical curve, but also by means of motion vectors in the measurement image. They allow conclusions to be drawn about the stability of the track bed.

Publish date: 15. September 2021 By Jörg Hepperle ()