Gaphor is the simple modeling tool

XSTAMPP (eXtensible STAMP Platform) is an open-source platform for safety engineering designed specially to serve the widespread adoption and use of STAMP methodologies (STPA and CAST) in different areas. XSTAMPP includes seven plug-ins.

FASTEN: FormAl SpecificaTion ENvironment - a set of DSLs to experiment with rigorous systems and safety engineering.

Awas: A tool for model navigation, dependency analysis and risk analysis of component based systems

Digital Engineering (DE) Digital Textbook

Code for a train gate STPA model that uses simulink design verifier, arduino and blender