A new method for repairing railway track irregularities using levelling and lining machines

We have developed a new method for repairing railway track irregularities with heavy mechanical machines. Levelling and lining operations in these machines are based on the so called 3-point measurement system with asymmetric chord spacing. To repair effectively track irregularities over the wide-range of wavelength, an absolute reference frame method is excellent but it requires the measurement of the actual track geometry before the repair work. In our new method such an extra measurement is not required. Instead the waveform restored or reconstructed by the inverse operation from the usual versine data is used. But a restoration is only able to be carried out in the limited range of wavelength and so not equal to the actual track geometry. Therefore the effectiveness of the use of such a partially restored waveform on the repair work is investigated. In the application of the new method several data processing techniques are required. In the curved track it is necessary to extract the component due to the fundamental track geometry which is different from a track irregularity, from the measured versine data, as precisely as possible. A new method is already successfully applied to the actual repair work.