[Technical Infrastructures as Products and Producers of Time]

During the last few years "time" has been an intensively debated topic among historians. This concept is increasingly being considered in the history of technology as well. For historical research on infrastructures, however, time still plays a minor role. This article takes up recent approaches and presents the relationship between networked infrastructures and time as reciprocal: In infrastructures, different epochs with their temporal contexts are deposited as layers of time. This is reflected not only in technical components of different ages, but also in organizational structures or action routines. Infrastructures produce time by influencing the ways persons, information or goods circulate through them. In this paper the use of the following metaphors for the analysis of these relationships are proposed: "time layer" and "palimpsest" for the consequences of their historicity materialized in the systems, "inscription" and "overwriting" for the underlying processes. The production of temporality by the infrastructures thus composed will be described as the "rhythms" that structure circulation. In sum, a complex picture emerges: the different time layers of an infrastructure contribute to the formation of rhythms.