Investing in low-emission and energy-efficient rail transport remains important for the future. Finland uses a broader track gauge (1524 mm) than is commonly used elsewhere in Europe (1435 mm), but the phenomena related to train movement are similar for both gauges. As train speeds increase and axle loads grow, they place greater stress on the track, leading to more damage and a higher risk of accidents, which in turn increases maintenance needs and costs.
“It is important to quickly repair track defects that could lead to accidents. This requires funding. Therefore, it is advisable to target track maintenance in a way that ensures traffic safety while also maximizing the benefit from the available resources,” says Tiia Loponen.
Field measurements and simulations
In her doctoral research, Loponen combined field measurements and simulations to examine how different types of rolling stock behave under various track conditions.
According to the findings, lateral rail wear and rail profiles shaped by wheel contact reduce the steering ability of rolling stock, which increases track loads. Track irregularities and abrupt geometric changes raise the risk of derailment, whereas increasing the track gauge in tight curves can help reduce loads.
“Moreover, the shape of rail wear—not just the amount of wear—affects how well the rolling stock is guided. This insight could lead to new maintenance practices, where the need to replace rails is assessed based on steering performance, not solely on wear limits,” she notes.
More targeted maintenance
Loponen’s research findings can be used to optimise railway track maintenance and to allocate track usage fees in a way that encourages the use of track-friendly rolling stock. She emphasises that increasing knowledge about the interaction between rolling stock and track helps to target maintenance efforts more effectively.
“Cost savings can be achieved by avoiding unnecessarily early maintenance. For example, allowing more rail wear than current limits permit—without increasing derailment risk—can reduce infrastructure costs. Extending the rail replacement interval could bring significant financial benefits,” Loponen explains.
Track defects can damage trains, and poorly maintained trains can, in turn, damage the track.
“In Finland, the track and trains are owned by different entities, which makes joint optimisation of maintenance costs challenging. When a train runs smoothly on the track, wear is reduced. This benefits both parties by lowering their maintenance costs,” she notes.
Doctoral Defense on Friday, October 24
The doctoral dissertation of M.Sc. Tiia Loponen, titled Vehicle-Track Interaction on Broad Gauge Railways, in the field of civil engineering, will be publicly examined at the Faculty of Built Environment at Tampere University on Friday, October 24, 2025, at 12:00 noon. The event will take place at the Hervanta campus, in Kampusareena auditorium A223 (Korkeakoulunkatu 7, Tampere).
The opponent will be Professor Zili Li from Delft University of Technology, and the custos will be Professor Pauli Kolisoja from the Faculty of Built Environment at Tampere University.
Read the dissertation: https://urn.fi/URN:ISBN:978-952-03-4115-2
