The Consolidated Rail Corporation (Conrail) was incorporated in October 1974. It was formed under the auspices of the United States Railway Association, a quasi-public agency established for the purpose of solving the problems of bankrupt railroads in the Northeast and Midwest. The Conrail photograph collection consists of a large number of images from its company files, but the majority of the material comes from its predecessor companies: Pennsylvania Railroad and Penn Central Transportation Company. These items are predominanatly composed of photographs, negatives, transparencies, lantern slides, and films.

Chartered in 1871, Reading Company was the holding company for the system of railroads, canals and coal mines assembled by the predecessor Philadelphia & Reading Railroad Company between 1833 and 1896. The collection consists of the corporate records of the Reading Company (1871-1976), the Philadelphia & Reading Railroad Company (1833-1896), the Philadelphia & Reading Railway Company (1896-1923), and 159 predecessors and subsidiaries.