Transitions are processes of systemic change where niches peripheral to a sociotechnical regime accumulate momentum, scale up and eventually transform its core. In contrast to this dominant narrative in transitions research, infrastructure systems exhibit the reverse process as change propagates from the regime core to its periphery. We explore this under-researched process in the case of digitalization in UK construction. We analyse six UK megaprojects that span more than 30 years as a single longitudinal embedded case, and show how the adoption of digital technologies driven by regime incumbents, seeds the processes of technology adaptation, aggregation, and system transformation. The adoption of digital technologies by incumbents is necessary to cope with megaproject scale and scope. Their adaptation to technology instigates organizational level change that starts at the regime core, accumulates with each project and makes these changes ripple across the industry and transform it.