High-Speed Railway Turnout Sub-Rail Foundations
In Germany, for the sub-rail foundation of turnouts, two types of track systems are utilized: ballasted and non-ballasted. In the case of ballasted track, existing railway lines' sub-rail foundations are employed within the turnout area. However, when sleeper lengths exceed 3.2m, sleeper resonance phenomena become evident, leading to the "ballast to powder" phenomenon caused by the beating of the track bed by the no-driving end of the train. To address these issues, long sleepers are connected using hinge joints, effectively mitigating these challenges.
On high-speed railway lines such as the route from Cologne to Frankfurt and the ongoing construction of similar lines from Nuremberg to Munich, non-ballast track systems are utilized. Here, the Rheda2000 long sleeper, partially comprising pre-stressed concrete, is employed. These long sleepers feature a triangular truss in the lower exposed part, with rail shoulders and plastic dowels at both ends. During construction, rail bolts allow for height adjustment to ensure proper fitting. Concrete sleeper turnouts must adhere to the EN13230-4 standard, ensuring adequate strength, rigidity, and stability. Unlike in the ballasted track system, long sleepers in non-ballast track systems are not connected using hinge joints.
In French high-speed railway turnout areas, all sleepers are concrete and must possess sufficient strength, rigidity, and stability. Sleeper lengths vary gradually from 2.6m to 4.8m, with tensioning forces controlled to 500kn. Similar to the non-ballast track system in Germany, these concrete sleepers feature rail shoulders and plastic dowels at both ends, ensuring proper alignment and stability without the use of hinge joints.