The Columbia River Gorge Commission hears an appeal Tuesday from Union Pacific Railroad on a proposed track expansion near Mosier, Oregon.

The proposed five-mile stretch would pass through the site of last year’s oil train derailment that spilled 40,000 gallons of crude oil and contaminated the town’s groundwater.

The Federal Railroad Administration ruled Union Pacific was to blame for the derailment. The agency found the railroad failed to maintain a section of track.

In November, Wasco County Commissioners unanimously denied Union Pacific’s proposal to expand its tracks on the Oregon side of the Columbia River. In December, Union Pacific appealed the county’s decision.

The Gorge Commission will hear oral arguments from the railroad and opponents of the proposal. Commissioners will deliberate in public and are expected to rule later Tuesday.