Across the twentieth century, hundreds of women worked as nurses, cooks, cleaners, and teachers on Mexico’s railroads. They have been overlooked in histories of the railroads and Mexican industrialization more broadly, their limited number perhaps suggesting that their work is not of analytical importance in understanding processes of economic development and class formation. On the contrary, these women’s work constituted many of the most coveted labor rights of the postrevolutionary railroad workforce, itself a symbolic vanguard of Mexico’s working class and one of the most important beneficiaries of the expansion of social and economic rights ushered in by the Mexican Revolution. The gendered division of labor characteristic of the railroads was neither accidental nor insignificant. Railroads used the feminization of the work of social reproduction to write off structural failures and predictable shortcomings in welfare provision as failures of femininity. Women became scapegoats for the consistent violation of workers’ rights through underfunding and understaffing. In tracing this process, the article models a historiographical and methodological intervention with broader relevance. It suggests that the social and labor rights that expanded around the world in the late-nineteenth and early-twentieth centuries must be studied not only from the vantage of legal or political history, but as themselves questions of social and labor history. Making these rights real depended on socially reproductive work that has often been marginal in accounts of industrialization and economic development. It is impossible to understand the political economy of social and economic rights without understanding women’s work.