This article reports on the results of a study on surveillance and plural policing in the Stockholm public transport system. More specifically, it analyses a SEK 500 million (EUR 55 million) investment called The Security Project, through which the Stockholm public transport authority seeks to address a perceived security deficit among its passengers. At its core, the Security Project was an investment in Sweden's largest CCTV system, and many other surveillance measures. The article describes how surveillance became central to addressing security concerns in the Stockholm public transport system. It applies a diachronic case study methodology and uses a framework that highlights centralisation of governance networks and normative cohesion as means to study plural policing and surveillance. The article addresses current debates on these topics, primarily Coaffee's and Duijnhoven's recent work on urban security. It aims to show how the roles of the police, private security and surveillance practices in general have been altered by the Security Project, and how the project produced contradictory effects through centralisation on the one hand, and a maintained (chaotic) diversity of policing on the other.