By the end of the nineteenth century, railway expansion had led to the formation of a technocratic bureaucracy in Chile and other countries in Latin America. Central to this formation were the engineers who oversaw and regulated both public and private railways. Recently, historians have begun to re-examine engineers’ roles in this period. By employing methods and theoretical framings from the history of technology, this article argues that engineering was an important framework through which state–capital relations evolved, making engineers pivotal actors in the evolution of political economy at the time.