Urban regime theory has become a favoured tool of analysis for students of city politics. It provides a consistent evaluative framework with which to analyse the operation of local politics in contrasting cities. Recent applications have sought to extend the reach of regime analysis beyond the US, and to integrate the theory with other urban political and geographical analyses. This paper reflects both of these concerns by applying the insights into power structures and coalition formation in city politics provided by regime theory, and particularly Stoker and Mossberger's (1994) typology of regime characteristics. This is valuable in informing the (re)emerging debates over the preferred spatial and functional structure of urban local governance in the UK. By comparing the development of policy in a particular field, urban rail transportation, the characteristics of two different local institutional mixes, the 'city-regional' and the 'public choice', are demonstrated to exert profound influences on the composition, operation and aspirations of local regimes. The differences in decision-making strategies and policy outcomes that arise are suggested to have significant implications for the preferred spatial structure of local authorities, and the level of public accountability they achieve. [ABSTRACT FROM AUTHOR]