The European Rail Traffic Management System (ERTMS) is a single European signalling and speed control system that ensures interoperability of the national railway systems, reducing the purchasing and maintenance costs of the signalling systems as well as increasing the speed of trains, the capacity of infrastructure and the level of safety in rail transport.
ERTMS comprises of the European Train Control System (ETCS), i.e. a cab-signalling system that incorporates automatic train protection, the Global System for Mobile communications for Railways (GSM-R) and operating rules.
Technical specifications for ETCS and GSM-R are published in the Control Command and Signalling (CCS) Technical Specification for Interoperability (TSI).
GSM-R provides voice communication for train drivers and signallers and provides data communication for ETCS. ERTMS and GSM-R rules are published in the Operation and Traffic Management TSI.
ERA plays the role of system design authority for ERTMS. In that respect, it must establish a transparent process to manage, with the contribution of the sector’s representatives, any system changes.
ERA is requested to identify all errors that potentially could not allow the system to provide a normal service and to publish as early as possible the respective solutions to correct them as well as the evaluation of their impact in the compatibility and stability of the existing ERTMS deployment. This work has been undertaken by ERA in cooperation with the sector and has resulted in a technical opinion (ERA/OPI/2017-2).
Within the scope of this assessment and provided that its recommendations are taken into account, the ETCS baseline 3 MR1 is backwards compatible with ETCS baseline 2.
A second baseline compatibility assessment has checked that:
The second baseline compatibility assessment also includes the analysis of the compatibility between trackside and onboard both within ETCS baseline 3 MR1 and within ETCS baseline 2, in the light of the problem description of the Change Requests included in ETCS baseline 3 R2.
This second baseline compatibility assessment confirms that the ETCS baseline 3 R2 is fully backwards and forwards compatible with the ETCS baseline 3 MR1, i.e. that ETCS baseline 3 R2 vehicles can run a normal service on ETCS baseline 3 MR1 trackside and ETCS baseline 3 MR1 vehicles can run a normal service on ETCS baseline 3 R2 trackside.
ERA organises and processes the Change Control Management (CCM) for the ERTMS specifications and related documents listed in Annex A of the Control Command and Signalling (CCS) Technical Specification for Interoperability (TSI).
A CCM procedure exists under the ERA Integrated Management System. This procedure is based on the former procedure originally approved by the ERTMS Control Group and takes account of the return of experience accumulated over the past years.
Any modification to the ERTMS specification is analysed via a Change Request (CR). CRs can only be submitted in the CCM tool by the representative bodies. More information about the submission of CRs can be found in the restricted ERTMS area.
The use of some ETCS variables requires co-ordination, including the definition of who is assigning new values. Care has to be taken not to assign identical values for different purposes or vice versa. Reasons for this may be functional or safety related.
Based on the functionality behind each variable, a list for the organisations responsible for assigning values to them has been established (see section 18.104.22.168 of Subset-054) and can be classified as follows:
National technical rules (NTRs) are one of the obstacles for the harmonised implementation of ERTMS and thereby, their numbers are to be reduced as far as possible.
The relevant NTRs have to be notified to the European Commission, using NOTIF-IT.
Currently, NTRs can be found at several locations at different national levels, in the ERA Reference Document Data Base (RDD) and in NOTIF-IT. In addition, several Member States have just started to elaborate their NTRs. This situation may create difficulties for organisations applying for a vehicle authorisation.
As a temporary measure, ETCS and GSM-R NTRs are provided below.
Feedback from ERTMS projects shows that ERTMS interoperability constituents and sub-systems contain restrictions and specific conditions of use. The Control Command and Signalling (CCS) Technical Specification for Interoperability (TSI) requires that such information should be provided during the certification process.
Therefore, ERA has developed a template and related guidelines to ensure that the deviations are described in a common and transparent way. The input for the template has to be provided by the Notified Body (NoBo) in collaboration with the applicant.
A control command and signalling system does not brake, i.e. it is not responsible for the braking system of the train, which will do the actual job. ETCS (and also some elaborated legacy systems) supervises both the position and speed of the train to ensure they continuously remain within the allowed speed and distance limits, and -if necessary- it will command the intervention of the braking system to avoid any risk of the train exceeding those limits.
To do so, the ETCS onboard computer must predict the decrease of the train speed in the future, from a mathematical model of the train braking dynamics and of the track characteristics ahead. This prediction of the speed decrease versus distance is called a braking curve.
From this prediction, the ETCS onboard computer calculates in real time braking distances, which will also be used to assist the train driver and to allow him/her to drive comfortably, by maintaining the speed of the train within the appropriate limits.
The ETCS baseline 2 specifications lay down the basic principles for the braking curves and the associated information displayed to the driver, but there is still no harmonised method/algorithm to compute them.
The convergence towards a stable specification of the ETCS braking curve functionality has now been achieved and is reflected in the ETCS baseline 3 specifications.
The ETCS braking curves algorithm consists of a complex set of equations. The Agency has developed a tool, which allows predetermining all the braking distances, as they would be computed by the ETCS on-board equipment. The tool allows capturing all train data (including the correction factor K_dryrst obtained from the Monte Carlo calculation) and trackside, which are relevant to the braking curve calculation and displaying graphically the braking distances so calculated.
Even a successful certification process cannot always exclude that, when an on-board CCS subsystem interacts with a trackside CCS subsystem, one of the subsystems repeatedly fails to function or perform as intended under certain conditions. This may be due to variance in national control-command and signalling equipment (e.g. interlockings), engineering and operational rules, deficiencies in the specifications, different interpretations, design errors or equipment being installed incorrectly.
Therefore, checks might need to be carried out to demonstrate the technical compatibility of the control-command and signalling subsystems in the area of use for a vehicle. The necessity of these checks should be considered as a temporary measure to increase the confidence on the technical compatibility between the subsystems. The possibility of executing those checks in a laboratory representing the trackside configuration to be made available by the Infrastructure Manager should be prioritized.
ETCS System Compatibility (ESC) shall be the recording of technical compatibility between ETCS onboard and the trackside ETCS part of the CCS subsystems within an area of use.
An “ESC type” is the value assigned to record the technical compatibility between an ETCS on-board subsystem and a section within an area of use. All sections of the Union network which require the same set of checks for the demonstration of ESC shall have the same ESC type.
Radio System Compatibility (RSC) shall be the recording of technical compatibility between voice or data radio on-board and the trackside GSM-R parts of the CCS subsystems.
An “RSC type” is the value assigned to record the technical compatibility between a voice or data radio part of the on-board subsystem and a section within an area of use. All sections of the Union network which require the same set of checks for the demonstration of RSC shall have the same RSC type.
The Agency shall set up and manage in a technical document the set of checks “ESC/RSC types” to demonstrate the technical compatibility of an on-board subsystem with the trackside subsystem.
Infrastructure Managers, with the support of the ETCS and/or GSM-R suppliers for their networks, shall submit to the Agency the definition of the necessary checks (as defined in CCS TSI section 4.2.17) on their network by 16 January 2020 at the latest.
For submitting the ESC-RSC, please send it to us by e-mail: firstname.lastname@example.org.
The Agency shall update the technical document within 5 working days. The Agency will assign a unique identifier to each ESC/RSC type which will be communicated to the Infrastructure Manager. The corresponding identifiers will be also included in the predefined list of values to be selected in RINF and ERATV.
Infrastructure Managers shall classify the lines according to ESC/RSC types in RINF, using the provided identifier.
ERATV users shall also include the ESC/RSC types that have been checked for the vehicles, using the identifiers in the technical document.
Infrastructure Managers shall submit to the Agency any changes on the referred checks for their networks, by using the same email (email@example.com) and making reference to the modified ESC/RSC type.