Method and apparatus to determine structural parameters of a railway track

A method of monitoring a railway track to ensure safe travel, the method comprising:

• determining structural parameters of a rail using a measurement system comprising:
• a railway car configured as a measurement vehicle, the measurement vehicle including a sensor array mounted on one side of a wheel and configured to measure at least vertical and/or lateral irregularities of the rail under influence of different loads at a plurality of points along the rail, and at different distances from the wheel of the measurement vehicle,
• the sensor array further configured to provide signals corresponding to said irregularities, the sensor array being positioned in the railway car adjacent to a contact point between the wheel and the rail;
• and
• a processor configured to process the signals from the sensor array;
• with the measurement vehicle moving on the rail, measuring at least the vertical and/or lateral irregularities of said rail with the sensor array along the rail, thereby providing the signals corresponding to the irregularities at the different distances from the wheel, and under the influence of the different loads;
• providing a model describing a deflection shape of the rail, wherein the deflection shape is dependent on the structural parameters of the rail and on loads on the rail, said model being stored in the processor;
• and
• comparing said irregularities under the influence of the different loads in order to separate deflection due to wheel loads from non-loaded geometrical irregularities, thus generating a measured deflection shape;
• generating at least one theoretical rail deflection shape using the model by varying the structural parameters and the load in the model;
• and
• comparing the at least one theoretical rail deflection shape with said measured deflection shape for each point along the rail;
• determining the structural parameters of the at least one theoretical rail deflection shape which best matches said measured deflection shape.