Completed on November 1, 1919, the railroad ran westward from a connection with the Oregon Short Line Railroad at Divide, following the Big Hole River upstream to the town of Wise River, Montana, also known as Allentown. From there, the railroad headed south into the Pioneer Mountains, terminating at the booming mining camp of Coolidge, where the Boston-Montana had constructed a 750-ton per day oil flotation mill and other developments.
The railroad was finished on November 1, 1919, connecting to the Oregon Short Line Railroad at Divide. It then traveled upstream along the Big Hole River to Wise River, Montana, also known as Allentown. From there, it headed south into the Pioneer Mountains and ended in Coolidge, a booming mining town where the Boston-Montana had built an oil flotation mill and other infrastructure.