In common with many countries, emergency departments (EDs) in Australia are under stress. To reduce 'access block' (where service demands exceed the ED's capacity) work processes in the ED of a public hospital were analysed using animated simulation. This article describes organisational culture changes supported by the use of simulation as an impartial form of analysis and communication. Data collected included time stamps and booking schedules in the imaging department (ID), semi-structured interviews and patient flow observations from the ED to the ID. Implementation of ID staff-suggested improvements resulted in a 25% increase in the capacity of the ultrasound department and a doubling of its ED cases. Improved communication between the ED and the ID, as a direct result of this project, has led to ongoing interdepartmental cooperation. One implication is that changes to health organisational culture can be assisted by computer simulations providing rapid and accurate predictions of change outcomes.