RAMS Requirements ERTMS Regional

Transcription

1 Handling Giltig från Versionsnummer Antal sidor ,0 8 Diarienummer Beslutsfattare Antal bilagor 0 Handläggande enhet, Handläggare BTA, Susanne Jansson, +46 (0) Ersätter RAMS Requirements ERTMS Regional

2 ,0 2 (8) Ändringslista Version Modifiering Gäller från Handläggare Godkänd A Nytt dok SJ 7.0 Ny text PEI RAMS 10 Innehållsförteckning

3 ,0 3 (8) Contents 1 Introduction Expectations Purpose Scope Abbreviations, terms and definitions Unique identification of each statement in the ERTMS Regional requirements Applicable standards General RAMS requirements Reliability requirements (R) Availability requirements (A) Maintainability requirements (M) Corrective maintenance Preventive maintenance Safety requirements (S) References... 7 Innehållsförteckning

4 ,0 4 (8) 1 Introduction 1.1 Expectations The ERTMS Regional system is intended to protect the users of the railway from hazardous situations and prevent the creation of hazardous situations. RAMS are cornerstones in achieving this. Therefore Banverket expects the system to have high reliability, high availability and require a minimum of maintenance. It is also expected that the system shall have satisfying safety. To achieve the required level of reliability, availability, maintainability and safety it is crucial to manage and monitor the requirements during the system s lifecycle. Therefore it is expected that the supplier plans and carries out necessary tasks in the phases for which the supplier is responsible. It is also expected that the supplier follows appropriate standards and has personnel appointed to those tasks. It is expected that the system has as few types as possible of hardware components replaceable on site thus required in spare-parts inventory. 1.2 Purpose This document specifies requirements on Reliability, Availability, Maintainability and Safety (RAMS). 1.3 Scope The boundary of the ERTMS Regional system (as specified in General technical Requirements Specification, GRS) is the boundary of the RAMS requirements. The RAMS requirements are applicable to the whole ERTMS Regional system, i.e. a maximum configuration of a specific application (including generic product and generic application). A maximum configuration is specified in General technical Requirements Specification, GRS [4]. 1.4 Abbreviations, terms and definitions Unique abbreviations, terms and definitions relevant to RAMS requirements will be explained in this chapter. EN50126 defines RAM failure categories. The definitions of RAM failure categories in this document differ from those in EN Whereas EN50126 defines failures in terms of resulting delays and costs, this document defines failure in terms of affected functions. The terms in this document are specific to the context of the ERTMS Regional system.

5 ,0 5 (8) The RAM failure categories are defined as follow: A Significant Failure is one that occurs in an ERTMS Regional system and fulfils any of the following descriptions: A failure, caused by the ERTMS Regional system that prevents or could prevent more than one train or shunting unit to move. A hazardous failure. A Major Failure is one that occurs in an ERTMS Regional system, is not a significant failure but does fulfil any of the following descriptions: A failure, caused by the ERTMS Regional system that prevents or could prevent one train or shunting unit to move. A failure that entails a more restrictive train movement than would have otherwise been the case in the absence of the failure. Balise failures are excluded. A Minor Failure is one that occurs in an ERTMS Regional system but that is neither significant nor major. Availability is defined as follows: Technical availability is the probability that a system or equipment is operating satisfactory at any point in time when used under stated conditions, where the time considered is operating time and active repair time. Preventive maintenance, administrative and logistic times are excluded. Operational availability is the ratio between the up-time and the total-time of a system or equipment including all restoration time (corrective and preventive time), administrative and logistic time. Hazardous failure is a failure that may put the signal safety equipment into a condition where the system doesn t prevent any of the following consequences: Collision between railway vehicles Railway vehicle derails Railway vehicle collide with road vehicle Mean time to repair, MTTR is defined as: Operational Standstill time for the system caused by fault on the system including fault diagnosis time and check out time, but not including logistic delay nor administrative delay.

6 ,0 6 (8) 1.5 Unique identification of each statement in the ERTMS Regional requirements To allow the unique identification of the RAMS requirements within the ERTMS Regional project, the letters RAMS (Reliability, Availability, Maintainability and Safety) precedes the number for each requirement in the document. Explanations and notes are not numbered. This information is for clarification and shall not be regarded as requirements. 2 Applicable standards RAMS1: For the ERTMS Regional system the following standards shall apply: EN50126 [1] EN50128 [2] EN50129 [3] 3 General RAMS requirements RAMS2: Both random and systematic failures shall be considered in all failure rates. 4 Reliability requirements (R) RAMS3: Mean time between failures, for a maximum configuration of a specific application of the ERTMS Regional system, shall be at least the following: Failure type Required time [hours] Mean time between significant failures (MTBF Si ) Mean time between major failures (MTBF Ma ) Mean time between minor failures (MTBF Mi ) (about 10 years) 3650 (about 0.4 years) 470 (about 20 days)

7 ,0 7 (8) RAMS4: In connection with demonstration of the reliability requirements, the time from which the failure occurs until the maintainer starts to repair can be assumed to 2 hours. 5 Availability requirements (A) Availability is influenced by reliability, maintainability and to some degree safety. Availability could be influenced by the supplier with high reliability on the technical system and with a clever design to be able to quickly correct any failures which may occur. Availability could also be influenced by other factors, e.g. the maintenance organisation. RAMS5: Technical availability of a maximum configuration of a specific application of the ERTMS Regional system shall be calculated according to A=MTBF/(MTTR+MTBF). RAMS6: The technical availability shall be at least 99,98%. The requirement is intentionally more restrictive than if the values of the reliability and maintainability requirements would have been used and calculated according to the formula above. It is the choice of the supplier to design the system in order to fulfil all requirements. The major failures will influence the availability the most. 6 Maintainability requirements (M) Maintainability requirements are important to make sure that, throughout the system s operational lifetime, the system returns to normal operation quickly and at reasonable cost. 6.1 Corrective maintenance RAMS7: Mean time to repair (MTTR) shall be maximum 30 minutes for significant failures. RAMS8: Mean time to repair shall be maximum 1 hour for major and minor failures. 6.2 Preventive maintenance RAMS9: Preventive maintenance shall not interrupt with the operation of the system. 7 Safety requirements (S) RAMS10: The maximum configuration of a specific application of the ERTMS Regional system shall have a Tolerable Hazard Rate (THR) of less than or equal to 1E-8 hazardous failures per hour.

8 ,0 8 (8) References [1] SS-EN Railway Applications The Specification and Demonstration of Reliability, Availability, Maintainability and Safety (RAMS), Final Draft issued June [2] SS-EN Railway Applications Communications, signalling and processing systems Software for railway control and protection systems, issued May 2001 [3] SS-ENV Railway Applications Safety related Electronic Systems for Signalling, European Prestandard issued June [4] ERTMS-R04026 General technical Requirements Specification, GRS