The Supreme Court ruled unanimously Tuesday that railroads may challenge state methods for determining the value of their property, a decision that could lower some railroad tax bills. The court sided with CSX Transportation Inc. in a case from Georgia in which the railroad argued that the state improperly instituted a new way of calculating its property tax that resulted in a nearly 50 percent increase in its tax bill from one year to the next.

The court reversed a ruling from the 11th U.S. Circuit Court of Appeals that prohibited the railroad, a subsidiary of CSX Corp., from challenging the method the state used to determine the value of the railroad's property.

A federal law bars states from discriminating against railroads by taxing their property more heavily than other commercial property. Chief Justice John Roberts said the law allows a railroad to go to court to try to show that the state's way of calculating market value is unfair.