The technodiplomacy of Iberian transnational railways in the second half of the nineteenth century

In the second half of the nineteenth century Portugal undertook an ambitious public works programme in order to develop the kingdom. In that programme, railways took a leading role, especially those routes that linked the main ports of the shoreline to Spain (and thence to France). To do so, a strenuous effort of diplomacy – or more specifically technodiplomacy – was required to convince Spain to accept cross-border links that served the goals of Portugal. In this paper I will analyse this technodiplomatic process and how two countries with different technological perceptions of railways managed to settle their differences and build five transnational links across their borders over the course of 40 years. I aim to add to the debate about the Iberian cross-border links from the point of view of the history of technology, in particular, and to the discussion about transnational technological systems, in general.