Effects of future mixed traffic on track deterioration - influence of freight trains with higher axle load and wider loading gauge

Higher axle loads, higher speeds and wider loading gauge are desirable improvements to make freight traffic on rails more competitive. The Swedish National Rail Administration (Banverket) aims at increasing the maximum axle load to 25 tons at increased loading gauge on major parts of the Swedish mainlines. On the same lines passenger trains are running at speeds of 200 km/h. Within a research project at the Royal Institute of Technology (KTH), the influence of this type of mixed traffic on the deterioration of the track was investigated. Dynamic vertical wheel-rail forces for freight wagons with different types of running gear are first simulated. To calculate track deterioration (mainly worsening of track geometry due to ballast settlement) the rails are regarded as beams on a Winkler foundation. With the so-called Zimmermann method the ballast pressure is determined. Then track deterioration is calculated with a method based on road test experiments. Track deterioration of a reference axle load collective is set to 100%. Deterioration due to other axle load collectives is calculated relative to the reference case. One conclusion of the investigation is that freight traffic stands for the dominant part of track deterioration. Track deterioration per axle might increase significantly by increasing axle load and loading gauge, especially in curves negotiated with uncompensated lateral acceleration. However, this can be compensated by an upgraded track. For the covering abstract see ITRD E125214.