The dynamics of systems integration: balancing stability and change on London's Crossrail project

Systems integration is essential for the design and execution of large, complex projects, but relatively little is known about how this task develops over time during the life cycle of a project. This paper builds on the concept of “disciplined flexibility” to describe how systems integration can be conceived as a dynamic process of maintaining stability, while responding flexibly to changing conditions. We examine the dynamics of systems integration through a case-study of Crossrail, the construction of London's new urban railway system, which will be called the Elizabeth Line when it opens for service. The balancing act of stability and change manifests during critical periods of the project life cycle as various interdependent systems evolve with different degrees of maturity. We identify how various types of reciprocal interdependencies in complex projects such as Crossrail – at the system and system of systems levels – require ongoing monitoring and control, and the mutual adjustment of tasks.