PTCSP - SAFETY ASSURANCE CONCEPTS (SACs)


"Positive Train Control Systems, 49 CFR Parts 229, 234, 235, and 236" requires the production of a PTC Safety Plan (PTCSP).  Section 2 of the PTCSP requires "a description of the Safety Assurance Concepts (SACs) that have been used for system development, including an explanation of the design principles and assumptions".

Appropriate and effective SACs are used to assist in the reduction of hazard risks to acceptable levels.

SACs are nothing new to system safety engineers.  Sometimes we refer to them as safety principles.  Aside from the PTC Systems Rule, for the well known SACs,  it has not been necessary for us to list design principles and assumptions since they too are well known and already documented in text books, guidelines, and standards.  We are all here afterall to focus our attention on safety, not to kill more trees.

Appendix C of the PTC Systems Rule states "The product design must include one or more of the following Safety Assurance Concepts as described in IEEE-1483 ...."  Does this make sense?

Perhaps you should consider one or more of the following: