2,700 railway bridges need maintenance. Where to start?

– Insight into how this bridge copes with aging and the stresses of passing trains gives us a greater understanding of how to approach maintenance of similar railway bridges in Norway and throughout Europe, says Rune Schlanbusch, Chief Scientist at NORCE and former Norwegian Coordinator for IAM4RAIL – a European Union project.

Schlanbusch and NORCE colleague Surya Kandukuri are onsite at Lundamo, south of Trondheim, Norway, to install state-of-the-art sensors.

Built in 1917, the beautifully constructed Lundamo steel bridge is representative for most Norwegian railway bridges. They were built to last for 100 years, which is right around now.

Out of 2,700 bridges in Norway alone, how do you determine which should be maintained or replaced first? Where do you even start? Is there a simple way to identify the bridges that must be replaced soon, and the bridges that still have a lot of years in them, without spending millions on technical examinations of each bridge?

– Our approach is to build a data model that will provide answers to these questions. Sensors are adding real-time data to improve the quality of the model and its output, says Schlanbusch.

More than 70 strain and vibration sensors have been attached to the Lundamo bridge. Sensor data is transmitted to NORCE and the Norwegian University of Science and Technology (NTNU) – both are scientific partners of the project and programme.

– Norwegian bridges are not likely to break down anytime soon, but it is vital to eliminate uncertainties related to life expectancy and to gain a better understanding of the total load, and how the bridge handles that load. Our mission is to develop an effective system for predictive maintenance, says Gunnstein Frøseth, Associate Professor at NTNU.

Expanding predicted lifetime based on safe evaluations and calculations has the potential to save the society of enormous costs, according to Klara Då, Head of Bridges at Bane NOR, the state-owned company responsible for operating, maintaining and building railways in Norway.

– Even though the theoretical lifespan has expired, bridges can very well be functional and safe for a longer period. We need more research to document remaining lifespan. We need more facts and more precise understanding. As a society we should keep utilizing existing infrastructure as long as possible. However, we need to understand the condition of the bridges, says Då.

IAM4RAIL is a €107 million, 4-year project, part of the Horizon Europe programme, comprising 94 partners across Europe. The Norwegian member is the Norwegian Railway Directorate with NORCE, SINTEF and the Norwegian University of Science and Technology as affiliated research partners.

Data collection at Lundamo started in September 2023. Based on the data the project expects to make significant improvements to its model within the project period of the next two years.

– The value of this project goes beyond the results that we will obtain from the Lundamo bridge. We share our know-how with peers across the continent and receive feedback from them. At the same time, we discuss new ideas that can be developed and form new partnerships with companies in the railway industry all over Europe. The working conditions of the Norwegian railways are quite unique and challenging. Research developed here can help showing what happens when results are applied in more extreme environments, says Stefano Derosa, Senior Advisor at the Norwegian Railway Directorate and Norwegian Coordinator for IAM4RAIL.