Mr. Luciano Cantone, University of Rome "Tor Vergata", ITALY
Mr. Robert Karbstein, DB Systemtechnik GmbH, GERMANY
Within the Innovative Programme 5 (IP5) of Shift 2 Rail (S2R) initiative (“Moving European Railway Forward”), The Open Call Project, Marathon2Operation (M2O), has cooperated with the FR8RAIL II Project to demonstrate the feasibility of freight trains equipped with Distributed Power System (DPS), using wireless communication to control the Traction Units (TUs). At this aim, the TrainDy software has been used as computational tool for Longitudinal Train Dynamics (LTD) and the Leaflet UIC 421 was applied as methodology in order to compare simulation results. The TrainDy software is considered the state-of-the-art tool for LTD computation by major European Railway Undertakings and the Leaflet UIC 421 provides a statistical methodology to accept new or modified operational scenarios for freight trains, which are beyond current regulations in terms of hauled mass and/or train length. The basic idea of UIC 421 is the “relative approach”, even if it does not discard the “absolute approach”. In short, the “relative approach” considers a train acceptable for regular operation if the risk level of the train is lower than the risk level of trains already in service; “the absolute approach” considers a train acceptable for regular operation if in-train forces are lower than (reliably) computed or measured admissible in-train forces. Since the cooperation among M2O and FR8RAIL II was based on the “relative approach”, only this approach will be discussed in this paper. The computation of in-train forces is crucial for new train consists to avoid derailment or disruption.
The paper shows the application of the relative approach in a particular way: the same trains (randomly generated) are simulated with and without the DPS system, considering different train operations and assuming communication among the TUs successful or not. In this way, the effects on in-train forces of DPS and wireless communication are immediately emphasized.
This paper reports the comparison between experimental measurements and TrainDy simulations and a series of analyses performed to compare the LTD of reference train against DPS train on level track, but also on up/down hill. The interesting conclusion that comes from this study is that the comparison among the reference and DPS trains does not depend on the track gradient, but rather on the train operations. Of course, the track gradient, especially when it is as steep as the one considered in this analysis, has a considerable effect on in-train forces as well as the exact train configuration (i.e., the wagon order within the train).
This paper could be used as guideline for similar analyses about in-train forces of new types of trainsets, e.g., implementing a new technology as radio DPS.