Emergence and variety of organizational forms in the industry of European railways’ certification bodies

New institutional theory has often originated studies on the variety of organizational forms deployed under the pressure of external and environmental factors, regardless of their efficiency implications. It has also emphasized the role of social pressures imposed on organizations that influence organizational practices and structures. Regulatory and normative factors are considered as able to affect the adoption of a specific organizational form, beyond pure economic rationality that would suggest the selection among those derived by practice. An articulated area of research in which verifying the adoption of alternative organisational structures may be provided by Notified Bodies, certification organisations operating in the European railway industry and established during the implementation phase of EU directives on trains interoperability.