Calero Gonzalez, Maria C.
(2025)
Integrating stability and flexibility in complex socio-technical systems: the case of the GB rail system.
PhD thesis, University of Nottingham.
Abstract
Conventional approaches to operational safety management rely on centralised hierarchical control structures, emphasising strict adherence to standards to minimise risks and uncertainty. This method aims to maintain stability and reduce variability in processes and behaviours, creating a predictable operational environment. This centralised control approach is dominant in modern complex sociotechnical systems in which safety is critical. Researchers have challenged this approach, arguing that the complexity and uncertainty in modern systems render preestablished, standardised control measures insufficient. They advocate for developing adaptive systems capable of navigating complexity and uncertainty, arguing that flexibility to handle contingencies in context by local actors is crucial.
These two approaches represent contrasting paradigms in operational safety management: one emphasising stability and central control, and the other prioritising flexibility and decentralised, local control. The challenge is to reconcile these contrasting approaches and find effective ways to integrate them.
The Great British (GB) railway system offers a unique opportunity to explore this contradiction and a clear example of the importance of such integration. Rail is a complex sociotechnical system where operational safety is managed through a centralised control approach. With recent and upcoming sector reforms, budget cuts, and post-pandemic changes in service demands, the GB rail industry is facing unprecedented uncertainty and pressures, necessitating increased efficiency and flexibility. Thus, it is essential to explore ways to integrate the existing safety management approach with alternative methods directed to increase flexibility and adaptation.
Overall, this doctoral research investigates that integration. The aim is to explore ways to increase flexibility in work processes and behaviours without compromising the system’s stability and safety. To do so, stability and flexibility are used as key concepts. The research adopts a dualist stance, investigating these concepts as separate yet not necessarily antithetical.
A variety of qualitative methods were employed in this research, resulting in four studies. Study 1 (Chapter 5) uses document analysis and interview data to explore how standards provide users with the flexibility needed to adapt to specific contextual circumstances. Study 2 (Chapter 6) uses interview data and document analysis to describe the railway standards development process, demonstrating how central control and operational realities are bridged through collaborative rulemaking.
Study 3 (Chapter 7) explores issues around stability and flexibility in railway operations management by interviewing individuals involved in rulemaking. The study draws conclusions regarding the risks, barriers, and preconditions of flexibility, highlighting important functions of centralisation. It also describes how the system faced and dealt with demands for high stability and high flexibility during the COVID-19 pandemic. Chapter 8 (Study 4) presents a case study conducted in a Rail Operating Centre. Using observations, interviews, and documents as data sources, the study examines the activities of rail infrastructure incident controllers, describing sources of stability and flexibility in real-life practice.
Overall, the main findings relate to:
• The system is performance-focused; safety is a quality and a precondition for performance.
• The risks associated with flexibility and the importance of maintaining a holistic view of the system, the risks and the operation. Mechanisms to bridge centralisation and decentralisation are described.
• The greatest barriers to increasing flexibility – and thus integrating both approaches – are social. The findings highlight the importance of interprofessional understanding and managing social processes to increase flexibility safely and efficiently.
• While the research describes stability and flexibility-enhancing mechanisms, understanding the degree of stability and flexibility needed is crucial. A framework to consider the mechanisms available in relation to differing operational needs is proposed (Chapter 9)
These findings have implications for both theory and practice, and the thesis concludes by reflecting on its contributions. The research provides insights useful for those involved in the safe and efficient management of rail operations. It also highlights issues that seem obvious to industry professionals but are often overlooked by researchers, provides empirical evidence to support safety research and theory, and offers a foundation for future investigations.
| Item Type: |
Thesis (University of Nottingham only)
(PhD)
|
| Supervisors: |
Ryan, Brendan
Macrae, Carl |
| Keywords: |
Safety, Rail, Resilience, Stability, Flexibility, Decentralisation, Centralisation |
| Subjects: |
T Technology > TF Railroad engineering and operation |
| Faculties/Schools: |
UK Campuses > Faculty of Engineering > Department of Mechanical, Materials and Manufacturing Engineering |
| Item ID: |
80433 |
| Depositing User: |
Calero Gonzalez, Maria
|
| Date Deposited: |
29 Jul 2025 04:40 |
| Last Modified: |
29 Jul 2025 04:40 |
| URI: |
https://eprints.nottingham.ac.uk/id/eprint/80433 |
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