Validating a Safety Critical Railway Application Using Fault Injection
Authors
Abstract
The need for safety assurance in critical systems demands for new tools and techniques, able to provide the required confidence while containing the costs relatively low. Fault Injection (FI) is a technique extensively used in several domains, such as space, but sporadically used in the railways. In this chapter we present a fault-injection tool able to complement the traditionalverification and validation procedures, to validate the safety of ProSigma, a SIL (Safety Integrity Level) 4 safety-critical system for railway signaling, implementing a TMR (Triple Modular Redundancy) architecture. This tool is based on the JTAG technology, and allows emulating the effects of hardware faults. Results from the FI campaigns show the ProSigma system exhibiting a high degree of tolerance to most of the injected faults, and unexpected
behavior in some cases. The results also confirm the efficacy of the proposed technique to help understand worst-case scenarios for validating safety of such a critical system.