Environmentalists are celebrating a victory in the fight over oil-train traffic along the Columbia River Gorge.

Wasco County voted on Nov. 2 to tentatively deny a plan by Union Pacific for four miles of new railroad track in Mosier, Ore., the site of a June oil train derailment.

Environmental advocates estimated the expansion could allow railroad to triple the number of trains through the Gorge. The railroad disputed those numbers.

The Wasco County Board of County Commissioners voted to reverse a decision by their planning commission. They expect to finalize the denial next week after the paperwork is corrected.

Among those challenging the initial decision to proceed with the rail expansion was the Yakama Nation.

Their argument that the plan violated their treaty rights helped convince the commissioners to deny the railroads plans.

"So far [the Yakama Nation] have successfully stood up to the largest railroad in the country," says Michael Lang, Conservation Director of Friends of the Columbia Gorge, which was among the groups challenging the railroad's plans.

Rod Runyon, Wasco County Commission Chair, calls the treaty rights "a key component" of the decision to reverse.

Further appeals on the issue are expected.

Update 9:30 pm:

Union Pacific spokesman Justin Jacobs says the extra track will "increase fluidity and efficiency where train traffic is severely 'bottlenecked.'

"Our project aims to reduce the number of idling trains in Mosier, The Dalles, Hood River, and other Gorge communities while mitigating train traffic delays to more efficiently transport the goods American families and businesses use daily," Jacobs adds. "We plan to continue working with the community to understand its concerns and address them moving forward."

Full press release from Friend of Columbia River Gorge:

The Wasco County Board of County Commissioners voted unanimously last night to deny the proposed Union Pacific rail expansion planned for Mosier, OR. Friends of the Columbia Gorge (Friends), Columbia Riverkeeper, and Physicians for Social Responsibility had appealed the Wasco County Planning Commission’s decision last month to grant Union Pacific their permit for a new track through Mosier, OR. The Yakama Nation also separately appealed the decision due to the project’s violations of tribal treaty rights and the National Scenic Area Act. The Board of Commissioners based their denial of the project on National Scenic Area laws prohibiting adverse effects to treaty rights. The Board of Commissioners will meet next Thursday, November 10, to adopt a final order denying the project.

“We applaud this decision by the Board of County Commissioners,” said Kevin Gorman, Executive Director of Friends of the Columbia Gorge. “The Planning Commission ignored tribal treaty concerns, environmental and scenic impacts on the Gorge, objections from the City of Mosier, and even the concerns raised by their own staff when they granted the permit last month. There were many reasons to deny this project, and the violation of tribal treaty rights is the most salient.”

The City of Mosier is still recovering from the Union Pacific oil train derailment, spill and fire on June 3 that leaked 40,000 gallons of crude oil and contaminated groundwater in the small town. The Federal Railroad Administration (FRA) released a report in June finding that Union Pacific was at fault for the accident because it failed to follow safety and rail inspection requirements.

A rail traffic report released by Friends last August found that increases in rail capacity from this expansion could be far greater than Union Pacific has claimed, potentially increasing rail capacity from about 35 trains a day to as much as 100 trains a day.