A geometrical approach to reduce calculation times in the definition of rail convoy speed profiles

The driving speed profile definition of a rail convoy, which may be adopted as a tool in planning and operational tasks, requires the continuous verification of safety conditions. The traditional approach, based on the evaluation of the braking distance at each iteration of acceleration or cruising phases, is generally time-consuming. In this context, our proposal consists of providing a geometrical approach for obtaining the same results as the traditional approach but in lower computational times. Preliminary applications to some trial networks have shown that, although in some cases (i.e. when the speed driving profile degenerates into a triangular motion diagram) the proposed approach requires a high number of iterations, the absence of braking distance evaluations implies reductions in terms of iterations, as well as in terms of calculation times, up to 98%.