These three institutions were built when Fairmount was still a rural suburban district of Philadelphia. Beginning in the 1830s, the city itself began to grow beyond its original boundaries, and a mixture of homes and factories sprang up on the district's southern fringes. The Baldwin Locomotive Works, the nation's largest maker of locomotive engines, was located on the southeastern edge of the future Fairmount neighborhood and was a major factor in development of the neighborhood south of Fairmount Avenue in the 1840s, 50s, and 60s.