Light rail: the semi-metro concept

Proposals to implement Light Rail transit in Australia have been the subject of considerable debate, particularly in Sydney. The purpose of this paper is inform aspects of this debate by drawing on the reasons that Light Rail was originally developed in Europe as a distinctive „semi-metro‟ rail application in the 1960s and 1970s before its international adoption. The paper has particular focus on using „semi-metro‟ Light Rail as a high quality alternative to Metro rail in an environment of budget constraint, or as a means to enhance service levels of present Light Rail proposals.The paper first presents a typology of transit systems to establish a clear understanding of the several forms of Light Rail. Secondly, it considers pertinent historic background of street tramway closures and the subsequent development and application of a respecified Light Rail Transit mode. Thirdly, the paper provides a high level analysis of the potential Sydney application of Light Rail. There are two key, related, points made in this paper. The first is that there has been a long history of demand for road space for motor vehicles that has been one factor in the removal of trams from the urban transit scene. This perceived conflict persists as a factor in today‟s Light Rail decision-making, despite recognition that streets should support a range of activities other than motorised transit. The second point is that street operation of transit is, in any case, often heavily compromised by motor vehicle congestion. While both of these matters may be managed to a degree by priority treatments, in certain situations the semi-metro concept – the original purpose of Light Rail – may offer advantages