Today services on the line are operated by the state-owned company Trenes Argentinos, the concessionary of Puente Alsina-Marinos del Crucero General Belgrano branch.

[1] In 1904, the Buenos Aires Province granted entrepreneur Enrique Lavalle a concession to build a metre gauge railway line between Puente Alsina and Carhué.

Some of the changes made by the consortium were the replacement of contractor Hume Hnos by Clarke, Bradbury and Co. (owned by Great Southern's manager's brother).

As the BAM line terminated at Puente Alsina, the company could not reach the capital city of Buenos Aires, which was part of its strategy to increase business.

Once the entire line had been inaugurated, the company acquired six Kerr, Stuart class Es that served until 1948 when the railway was nationalised, at which time these locomotives were sold.

Sentinel-Cammell locomotives, constructed jointly by Sentinel Waggon Works and Metro-Cammell, operated suburban services on the main line.

Some British owned companies (such as Great Southern Railway) responded by acquiring railcars from Drewry Car Co. By this time, BAM carried very few passengers, and was losing money.