Railway applications - Measurement of vertical forces on wheels and wheelsets - Part 3: Approval and verification of on track measurement sites for vehicles in service
This standard is related to EN 15654-1, Interoperable 'in-service' rail vehicles, that lays down minimum technical requirements and the metrological characteristics of a system for measuring and evaluating a range of vehicle loading parameters during operation in service. The aim of this standard is to verify, that these measurement sites fulfil requirements on measuring uncertainty and the evaluation process including the reaction time after passing the last axle the measurement site. Furthermore different types of limits and tolerance fields are to be specified based on a risk evaluation and acceptance according to EN 50126. For the resulting different required safety levels requirements for tolerance fields, confidential ranges and factors of extended uncertainty are to be derived. In order to obtain the comparability and reproducibility of measurement results on all European networks under different boundary conditions it is necessary to subject measurement sites to calibration during the type approval, site assessment tests and periodical ongoing tests. The description of these standardized tests is part of the scope of this standard, as well as a process to determine the uncertainty level of the measurements from these tests. The required evaluation process for determination of measuring uncertainty and the assignment to an accuracy class is described and standardized for any speed inside a defined calibrated range under defined conditions for reference trains and operating conditions. For clarification examples of uncertainty evaluations are given in an Annex. As all measured results must be assigned without errors to a certain wheel or axle of the measured train independently from the direction of travel of the train, a standardised coordinate system and a standardised orientation system is defined. As the accuracy of a measurement depends significantly on the vehicle characteristics, the conditions of reference trains, their minimum number of vehicles and their characteristics are defined in a sufficiently exact way. Inert characteristics of interoperable vehicles and reference vehicles together with characteristics of the track related to dynamic behaviour of the vehicles lead to a definition of minimum lengths of the measuring sites to ensure reproducibility in all networks. The required accuracy for safety-related measurement sites depends on the assessment quantity and the related limit together with its tolerance field. The process to determine the minimum required accuracy range from the tolerance field of a limit assigned to an assessment quantity is specified in this standard. The choice of the assessment quantities and the definition of the related limits and tolerance fields are not covered by the scope of this standard. The processes of the type approval, the site assessment tests and ongoing tests depend also on the safety relevance of measurements. It is distinguished between directly safety-related measurements, indirect safety-related measurements and non-safety-related measurements. For directly safety relevant measuring sites, measures and corrective actions are defined to avoid an intolerable risk. For indirectly safety relevant measuring sites, measures and corrective actions are defined to reduce an undesirable risk. For non safety relevant measuring sites, measures are defined to optimize the economic efficiency of the railway. The reported information is classified in informal, urgency and alarm reports. The tests described in this standard do not impose any restrictions on the design of measurement sites which fulfil the requirements according to this standard, on the types of vehicles that can be monitored, or on which networks or lines the measuring system can be installed. It is out of the scope of this standard to assess functions related to the track signalling or to the train control systems.
Planned document number
DIN EN 00256763