Beginning operations in 1893, the Butte, Anaconda & Pacific Railway (BA&P) began to electrify much of its system in 1912. Never a very large railway, at its peak it had 135 miles of track, 75 of which were electrified. Though it was a common carrier, hauling passengers and freight, its sole reason for being was to haul copper ore from the mines at Butte to the smelter at Anaconda. The railway was a wholly owned subsidiary of the Anaconda Copper Mining Company, which, incidentally, owned pretty much everything else in Anaconda, as well.
The mainline, 27.5 miles of track between Butte and Anaconda, would have seen tens of thousands of these hopper cars, loaded with copper ore, pass along its tracks. At one time the railway owned hundreds of these hopper cars which ran back and forth endlessly between the mines and the smelter.