Achieving Systems Integration through Interoperability

The following paper presents a case study demonstrating how systems integration can successfully be achieved in a large system of systems – the California High-Speed Rail System (CHSRS) – through the concept of interoperable interfaces and the development of modular and interoperable constituent systems – the CHSRS projects.

The author, Oliver Hoehne, presented the paper at this year’s INCOSE (International Council on Systems Engineering) virtual international conference, during which he was a recipient of the 30th Annual International Symposium Best Paper Award.


This paper provides a case study on system of systems engineering (SoSE) being performed in a multi-billion-dollar program – the California High-Speed Rail System – viewed from the systems integration perspective. The paper discusses why the subject program of projects (PoP) can be viewed as a system of systems (SoS), identifies the SoSE challenges faced, describes the SoSE activities performed, and summarizes the achieved outcomes and conclusions as of today.

Specific SoSE challenges discussed include SoS authority, leadership, architecting, collaboration, integration, and emergence. The paper reviews how decision-making in independently operated and managed constituent systems (projects) resulted in unanticipated SoS emergent behavior, which is one of the key challenges in the engineering of SoS.

The paper further discusses the performed SoSE activities, including an international best practice review, the tailoring of SoSE to the specific SoSE challenges, and provides examples where SoSE principles are being applied to perform successful SoS integration.


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To read about the California High Speed Rail program, click here.

To explore WSP’s systems integration (SI) approach, continue to the SI hub page.