Reconstruction of the Baltimore and Ohio Railroad Roundhouse and Shop Complex began soon after the American Civil War ended in 1865. The complex included two roundhouses and two major shop buildings, with the West Roundhouse as its centerpiece. Construction of the roundhouses began in 1865; the West Roundhouse was completed in 1866, the Bridge and Machine Shop and the Frog and Switch Shop were completed in 1867, and the East Roundhouse was completed in 1872. The Baltimore and Ohio Railroad rebuilt quickly to keep pace with competition as postwar western expansion in the United States advanced and railroad reconstruction and growth helped make that expansion possible. Architects John Niernsee and James Nielson designed the shop buildings, while the two roundhouses were based on designs developed by Albert Fink, a German-born and educated engineer with the Baltimore and Ohio Railroad and an important figure in the evolution of civil engineering in the United States. Working with Benjamin H. Latrobe, Jr., Fink developed early-1850s designs that used cast-iron framing components to support the walls and roof structures of roundhouses at Grafton and Piedmont, West Virginia. Those designs were adapted for the Martinsburg roundhouse, the only surviving structure using this design. Fink later became an important designer of railroad bridges and structures, a respected railway economist who helped establish a regulatory framework for American railroads that aided their financial recovery in the late 1800s, and in 1880 he served as president of the American Society of Civil Engineers.
