Dr.-Ing. Stefan Doersch, DB Systemtechnik GmbH, GERMANY

Mrs. Maria Starnberg, DB Systemtechnik GmbH, GERMANY

Dr.-Ing. Haike Brick, DB Systemtechnik GmbH, GERMANY

In the latest amendment to the TSI Noise, the Commission Implementing Regulation (EU) 2019/774 from year 2019 (TSI NOI EU 2019/774, 2019), the term “quieter brake blocks” was introduced. The purpose was to distinguish between brake blocks that cause a high rolling noise level by roughening the surface of the wheels and quieter brake blocks with acoustic properties that better correspond to the pass-by noise limit for freight wagons. However, it has remained an open point which methods and procedures should be used for the assessment of the acoustic properties of new brake blocks. This open point shall be closed in the new revision of the TSI Noise, which will become effective in year 2022. It requires a new acoustic certification procedure for brake blocks to be developed.

A new procedure for the acoustic certification of new brake blocks should be reliable, easy to use and less expensive in terms of time and costs than full scale pass-by noise measurements in field. These conditions could be fulfilled by a certification procedure based on the wheel roughness level caused by the specific brake block. The relationship to the TSI-noise limit value can be established by defining reference values for the rail roughness and transfer function according to the well-established rolling noise model. Besides the certification procedure, a practical method should be defined how to generate and assess the wheel roughness that is characteristic for a specific brake block product.

This project is financed by the German Centre for Rail Traffic Research in cooperation with the Federal Railway Authority and executed by DB Systemtechnik GmbH. The objective of the presentation is to introduce the research project “Acoustic Certification of New Composite Brake Blocks”. This presentation summarizes the project work so far and gives explanations and background knowledge to the development of the methods as well as to railway noise. A calculation example is given to comprehensibly demonstrate the proposed procedure.

At the time of the EuroBrake conference the project is still ongoing, and the final results cannot yet be presented. The focus for the discussions is to put on the practicability of the methods and the needs of the user regarding for instance documentation, required efforts or material and qualification.

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.