Railway operating procedures: regulating a safety-critical enterprise

Most railway systems throughout the world base the safety of their operation on strict regulation through (standard) operating procedures. The drawing up of those as well as their effect on the overall efficiency and safety of the system can be greatly enhanced by viewing the railway as an enterprise and the operating procedures as a model enacted by human resources. The paper examines the characteristics of those models and gives examples based on the author's experience in Attiko Metro, the new Athens metro system, currently under construction.