This report provides a framework for making reliable comparisons of the efficiency of rail systems. Efficiency is of concern to all governments but measuring it for railways is challenging. This is because of the complexity of providing rail services and the diversity of business models adopted to deliver them. Restructuring of the sector in many countries makes trends in costs and efficiency particularly difficult to track. There are also trade-offs to be made in how detailed the analysis needs to be and the availability of consistent data over time. The report proposes a balanced scorecard for characterising performance.