Tramways Revisited: An Analysis of the Role of Tramways in Urban Transportation during the Twentieth Century

Article excerpt

ABSTRACT: The structure and evolution of tramway and metro networks are studied in this article using two models involving addition/accretion and expansion/diffusion modes of growth, respectively. Data for the total length of tramway and metro lines can be satisfactorily correlated with total population of conurbations via single relationships involving, linear variations of the former with both the total population and its square root. The evolution of public transport in Valencia (Spain) during the twentieth century is discussed with respect to such models.

Introduction

The problems of urban transport need to be studied, among other factors, in the context of the evolution of urban structure. As pointed out in several classical works (e.g. Dyos, 1961; Warner, 1962) there is a close connection between the technological evolution of public mass transport and urban structure. Historical studies have emphasised the importance of the development of suburban railways and street railways in the urban evolution of US conurbations at the end of the nineteenth century (Holt, 1974). In this sense, the size of the city, urban topography, demographic growth, transport policy, etc, are variables that differ considerably from one urban area to another (Cheape, 1980). As pointed out by Pacione (2001) and Diamond (2002), the land use pattern, size of the city, its demography, local policy and socioeconomic constraints are linked in a complex series of relationships that make generalisations or simplifications difficult.

During recent decades a major problem emerging in almost every European country has been the growth of urban road congestion, associated with the growing importance of car ownership and use. Awareness of the various economic and environmental problems arising from unlimited car traffic has stimulated the development of conventional underground and suburban railways and, in particular, the emergence of light rail systems (Knowles, 1992). A prominent feature of recent urban development in Europe has been the decline of city centres; the emphasis in town planning is now more on conservation and ecology (Simpson, 1994), factors which in turn influence the development of transport systems.

During the first half of the twentieth century, mechanised urban transport in European cities consisted mainly of trams, which until the 1950s dominated urban transport and constituted an essential tool for social and economic development. The demographic and structural evolution of modern cities was closely related to the growth of an urban transport network, as studied by Thomas (1988) in the case of Moscow, and by Machon and Dingsdale (1989) in the case of Budapest. There are two contrasting ways of viewing this relationship: a) the structure of urban transport results from the selection of a series of privileged connections to a pre-existing urban structure; b) urban growth is strongly influenced by the structure of urban transport, and takes place preferentially along selected pathways where an efficient transport system already exists.

Since tramways provide a stable but flexible lattice of urban linkages, it makes sense to study the relationships between urban structure and urban transport during the period when trams were the dominant form of transport in cities. Such a study will help to establish whether or not there are significant correlations between urban growth and structure, and the development and configuration of a network of tramway lines.

The purpose of this article is to present a mathematical model for describing the growth of urban transport networks based on observable parameters. The following questions are addressed:

* Is it possible to develop mathematical models that can be used for such analysis in terms of observable parameters?

* To what extent can this kind of analysis of transport systems aid the understanding of urban growth?

* To what extent can possible relationships between numerical parameters be of value in describing the evolution of urban transport networks in different cities across time? …