Infrastructures of circulation, transportation, and communication play a central role in Luxemburg’s work in political economy as well as revolutionary strategy. This paper seeks to reconstruct and develop a theory of capitalist infrastructural expansion drawing from a variety of Luxemburg’s writings. In Accumulation of Capital, infrastructural expansion – namely of railroads – plays a central role at all stages of capitalist accumulation. Railroads act as a site of military and state investment for introducing the commodity economy to non-capitalist sectors and eventually for the “capitalist emancipation of the hinterland.” At the same time Luxemburg rejects the progressive character of these infrastructural endeavours, and she argues that they will not be a genuine “stamp of progress in an historical sense” until capitalism has been destroyed. It is no coincidence then that her political writings prominently feature figures such as railway and postal workers, who are strategically positioned to strike at the infrastructures of imperialism. A Luxemburgist theory of infrastructure has important relevance for contemporary debates around the expansion and ownership of Internet infrastructures. The past decade has been marked by various calls for new models of Internet ownership. These include The Public Service Internet Manifesto, the Democratic Socialists of America’s Internet for All Campaign, Tarnoff’s Internet for the People, Téwodros Workneh’s “Case for Telecommunications Commons in Ethiopia,” and netCommons Project’s vision for community networks. Such calls for a publicly owned and funded Internet risk reproducing some of the dynamics Luxemburg describes in her account of the history of railroads, canals, telegraphs etc. Namely, such calls parallel the state subsidising of an infrastructure that seeks out new sites of accumulation and extraction. This is not to say that such endeavours should be wholly abandoned, but must fit into a broader anti-capitalist political program, otherwise such infrastructural ...