How is such a large and far-flung collaboration managed?
Each detector subsystem has its own management team. At the same time, the ATLAS Executive Board and Spokesperson maintain general oversight of the Project. The Technical Coordination team is responsible for making sure that all the separate subsystems can fit together. In parallel, there are national representatives whose functions are to oversee the distributions of resources from each participating country to all the collaborating groups from that country, and make sure that those resources are well-used.
The Collaboration Board sets out the policy issues, and is not involved with the execution, which is the domain of the management. However frequent contacts between for example the Spokesperson and the Collaboration Board Chair ensure that policy issues are properly handled, and that fair solutions are found for difficult problems. Finally one should not underestimate the importance of direct contacts between individuals and teams with the collaboration management.