Formal methods for railway control systems

Abstract

We wish to model railway control systems in a formally precise way so that product lines can be adapted to specific customer requirements. Typically a customer is a railway operator with national conventions leading to different variation points based on a common core principle. A formal model of the core product must be precise and manipulatable so that different feature variations can be specified and verified without disrupting important properties that have already been established in the core product. Cyber-physical systems such as railway interlocking, are characterised by the combination of device behaviours resulting in an overall safe system behaviour. Hence there is a strong need for correct sequential operation with safety "interlocks" making up a process. We utilise diagrammatic modelling tools to make the core product more accessible to systems engineers. The RailGround example used to discuss these techniques is an open source model of a railway control system that has been made available by Thales Austria GmbH for research purpose, which demonstrates some fundamental modelling challenges.

Evaluation Framework for Key Performance Indicators of Railway ITS

“…The main contribution of this paper is twofold: (1) development, classification, and evaluation of KPIs for railway ITS, and (2) identification and evaluation of indicators for assessing railway ITS and their impacts using the Delphi and GAHP techniques. Moreover, the developed framework could be applied for uspostavljen kroz četiri glavna koraka: (1)…”

“…In the context of rail transport, railway ITS are systems working in a synergy of sensors, communications, computing, and intelligent control used for various aspects of rail system management and control, i.e., customer service, planning and scheduling, dispatch, block control, interlock, and speed control. In terms of rail transport, an example of such a complex system is the train control system [1]. Railway ITS aims at meeting important technological and economic objectives, such as increased capacity and asset utilization, improved reliability and safety, higher customer service levels, better energy efficiency and fewer emissions, and increased economic viability and profits [2].…”

“…(1) development of a comprehensive set of KPIs based on the papers related to evaluation of ITS found during the literature review and on the authors' knowledge (the initial set of KPIs was defined by the authors); (2) selection of experts for validation of developed KPIs and their classification, as well as evaluation of KPIs' importance through the Delphi technique; (3) application of GAHP for calculation consistency of returned questionnaires and weights of KPIs; (4) presentation of the strengths, weaknesses, opportunities, and threats (SWOT) analysis for the developed KPIs.Step 1: Development of indicatorsIn order to evaluate railway ITS and their effects on the performance of railway transport, an appropriate set of indicators must be developed. The starting or Delphi methodCheck of consistency of returned questionnariesCalculation of KPIs weights based on group judgments…”

Compositional modeling of railway Virtual Coupling with Stochastic Activity Networks

“…Moreover, we plan to strengthen model validation by leveraging results obtained from additional models or diverse parallel modeling. Extensions to reliability, safety and security modeling based on (semi)formal methods are also planned as future developments [FFG14,Fla12].…”

A Survey on Formal Specification and Verification of Smart Mass Transit Railway Interlocking System

“…The paper by Fantechi et al [68] discussed in the context of Intelligent Transport Systems (ITS), how to use formal methods to model and examine railway control systems. Also, elaborated on the exclusive session of 'Intelligent Transport Systems' organized within the ISOLA12 conference.…”