Methodology to admit new freight trains to international traffic according to the UIC

Current version of UIC Leaflet 421 provides a methodology based on statistical analysis to accept train compositions whose limits exceeds 2500t and 700m (locomotives excluded), for international traffic. This methodology does not consider explicitly trains with distributed traction/braking and their most relevant degraded modes. The paper shows a more general methodology to build statistically virtual trains, considering boundaries in terms of both train mass and length. The UIC approved TrainDy software can compute the longitudinal train dynamics (LTD) of these trains efficiently and accurately. The paper applies the new UIC Leaflet 421 to trains with distributed power and braking where the Traction Units (TU) communicate by means of GSM-R radio. Results show that in-train forces for 1500m train, heterogeneously loaded, carrying up to 4800t, with four TU, are similar to those of already running trains, at least in nominal mode, i.e. when there is a proper communication between the TU