Infrastructures in the transport and communication sectors were high on the agenda of supranational European integration after 1945. Nevertheless, European cooperation continued on well-trodden paths. New European organisations were established with an institutional design that built on established governance structures from the interwar period or even earlier. This article seeks to explore continuities in the governance of cross-border infrastructures from the interwar to the post-war period. It argues that transnational expert communities and cultures of standardisation emerged, which the infrastructure experts were keen to protect and persist. The article compares transport and communication to isolate common patterns and differences.