SIOUX FALLS, S.D. (AP) -- Two opponents of the Dakota Minnesota & Eastern Railroad's coal train project say they are filing a federal lawsuit to try to stop DM&E's plans.

The Sioux Falls-based railroad wants to build new track and renovate existing track so it can haul Wyoming coal east across South Dakota and southern Minnesota for shipment to power plants.

The Sierra Club and Mid States Coalition for Progress say their lawsuit is based on a 2003 ruling by the 8th U.S. Circuit Court of Appeals. The court said that when the federal Surface Transportation Board approved the DM&E project, adequate attention was not paid to the environmental impact of burning the additional coal the railroad would provide power plants, the Argus Leader of Sioux Falls reported online on Friday.

The court told the STB to review its approval based on that and several other issues. After its review, the agency decided it had complied with the court's demand and reaffirmed its approval.

"To us, the biggest social issue of the day is what we are doing to the planet's atmosphere because of (President) Bush's decision to convert us to a coal-based electrical society," said Jim Dougherty, a Sierra Club lawyer.

"We were hopeful after the court's last order that finally we would have a national review of what it means to burn another 10 million tons of coal a year, and instead they just punted," he said of the STB.

"There is no more important issue to the Sierra Club. This has always been what this case is about."

Sam Clauson of the South Dakota Sierra Club chapter said all the facts should be on the table.

The DM&E has said its project is environmentally sound.