Oregon Short Line Railroad

Between McCammon and Pocatello, Idaho, the line was shared with fellow Union Pacific subsidiary Utah & Northern's grade by adding a third rail to the 3 ft (914 mm) narrow gauge track to accommodate the 4 ft 8+1⁄2 in (1,435 mm) standard gauge cars.

The Southern Pacific had built tracks as far east as El Paso, Texas, and would, in 1883, become a transcontinental railroad in its own right.

The Oregon Short Line also was meant to halt the OR&N's continued eastward expansion at the Idaho-Oregon border.

The Oregon Short Line Railroad was incorporated in February 1897 and purchased the property of the OSL&UN later that month.

The OSL was independent for a short period of time until October 1898 when the newly reformed Union Pacific Railroad took control of a majority of the board of directors.