The Buenos Aires Midland Railway (BAM) was a British-owned railway company which operated in Argentina where it was known as Ferrocarril Midland de Buenos Aires. The company built and operated the metre gauge line between Estación Puente Alsina and Carhué in Buenos Aires Province. Today the line as far as General Belgrano is part of Línea Belgrano Sur which has been operated by UGOFE since 2007.
In 1904 Enrique Lavalle was granted the concession by Buenos Aires Province to construct the line, and the BAM company was formed. Soon after construction of the line began in 1907 the company entered into conflict with the French-owned company, Ferrocarril Compañía General de Buenos Aires, which was also building railways in the same part of the Province. Eventually an understanding was reached between the two companies and the line was finally opened to Carhué in 1911.
The original plan was to boost the importance of the line by extending it from the terminus in Puente Alsina into the centre of the nearby city of Buenos Aires. However, the fact that the company held a concession from the Province, made it impossible for them to enter the territory of the national government.
The route passed through rural areas with very small towns which generated little passenger traffic. This fact, combined with the effect of intense competition from the nearby services operated by the Buenos Aires Great Southern Railway, the Buenos Aires Western Railway and the CGBA, meant that, by the mid 1930s, passenger traffic on the BAM had become almost insignificant.
When the entire Argentine railway network was nationalisation in 1948, during Juan Peron's presidency, the BAM became part of the state-owned company Ferrocarril General Manuel Belgrano. track gauge ?