scope:

This European Prestandard specifies the track alignment design parameters, the rules and the values that shall be used to determine the maximum operating speed for both new and existing lines. Alternatively, for a given specified speed, it defines the track alignment design parameters either for a new line or an upgraded line. The track alignment designer is free to specify the values most appropriate for the various parameters, when considering safety, geographical, engineering, historical and economic constraints. These values are defined in the contract document. However, the choice should be such that the selected values are no worse than the maximum (or minimum) limiting values for the safety-related parameters. Whenever necessary, the track alignment designer should take into account any specific requirements of the appropriate national standards.