The U.S. Supreme Court is set on Tuesday to examine the extent to which federal agencies must review the environmental impact of projects they regulate in a dispute over a proposed railway in Utah that was challenged by environmental groups and a Colorado county.

The 88-mile Uinta Basin Railway, if built, would connect the remote, oil-rich Uinta Basin to the rest of the country and refineries on the Gulf Coast. The railroad could quintuple the region’s oil exports, according to a 2021 environmental review.

The Supreme Court seemed to favor a Utah oil railroad expansion in arguments on Tuesday, but appeared more skeptical of putting strict new limits on a key national environmental law. The justices were weighing a multibillion-dollar project that could quadruple oil production in the remote area of sandstone and sagebrush.