Safety and availability evaluation of railway operation based on the state of signalling systems

Abstract

A framework is presented to evaluate the safety and availability of the railway operation, and quantifying the probability of the signalling system not to supervise the railway traffic. Since a failure of the signalling systems still allows operation of the railway, it is not sufficient to study their effect on the railway operation by considering only the failures and delays. The safety and availability are evaluated, handling both repairs and replacements by using a Markov model. The model is verified with a case study of Swedish railway signalling systems with different scenarios. The results show that the probability of being in a state where operation is possible in a degraded mode is greater than the probability of not being operative at all, which reduces delays but requires other risk mitigation measures to ensure safe operation. The effects that different improvements can have on the safety and availability of the railway operation are simulated. The results show that combining maintenance improvements to reduce the failure rate and increase the repair rate is more efficient at increasing the probability of being in an operative state and reducing the probability of operating in a degraded state.

A Quantitative Approach for the Likelihood of Exploits of System Vulnerabilities

“…A large amount of work has been done for analysing the reliability and availability of the system e.g. [3,8,9]. In [3] the railway operation is analysed based on the failure and maintenance data obtained from the Swedish infrastructure manager for the automatic train control signalling system.…”

“…[3,8,9]. In [3] the railway operation is analysed based on the failure and maintenance data obtained from the Swedish infrastructure manager for the automatic train control signalling system. The paper uses a classical state-space Markov chains approach with stochastic transition rates for analysis.…”

“…There are many approaches for modeling and analysis/simulation of the reliability and availability of systems such as Markov Chains [1][2][3], eDSPNs (extended deterministic and stochastic Petri nets), colored Petri nets, or Faulttrees. Dependability patterns (e.g.…”

“…In Sect. 3.1, the Architectural Analysis for Security (AAFS) [3] approach has been illustrated for designing a secure system based on the architecture of the system under consideration. Section 3.2 mentions categories of component failures and explains why stochastic HW failures and cyber-attacks are considered for analysis.…”

Simulation analysis of the effect of doubling and electrification on the reliability of the rail networks: A Case Study of Tehran-Mashhad railroad

“…Mathematical optimization models have been extensively employed to measure train delays and to determine the train timetables as well as the operational capacity; see e.g. Corman, D'Ariano [8], [9], and Morant, Gustafson [10]. In addition, simulation approaches seem to be an effective and promising method to appraise the trade-off between capacity and reliability [11].…”