Barahona

For more than half a century, the Union Pacific Railroad (“Union Pacific”) has leased land under 1,800 miles of its right of way to Santa Fe Pacific Pipelines, L.P. (“SFPP”), which uses the land for a petroleum pipeline. In a suit by landowners challenging Union Pacific’s ability to lease the land, the district court held that (1) the acts of Congress conferring the right of way authorized Union Pacific to use the right of way only for a “railroad purpose,” and (2) the pipeline did not serve such a purpose. It then certified those issues for interlocutory review pursuant to 28 U.S.C. § 1292 (b). We granted permission to appeal and, for the following reasons, disagree with the district court’s conclusions.

I

A. Historical Background

In the mid-19th century, the vast expanse of territory west of the Mississippi River “remained a largely untapped resource,” Leo Sheep Co. v. United States, 440 U.S. 668, 670 , 99 S.Ct. 1403 , 69 L.Ed.2d 677 (1979), in part because the nation’s long-distance transportation network could not keep pace with its expanding frontier. The railroads bridged that gap. ■

Enthusiasm for a transcontinental railroad was initially offset by fierce…