(Corbett, OR)  --  The Multnomah County Sheriff's Office says a 92-car Union Pacific train was halted in the Columbia River Gorge when a diesel fuel leak was discovered.  The train was headed east from Portland yesterday and authorities believe the fuel leak was caused by a broken cap on a fuel filter.  Union Pacific officials say the diesel leak may have been between 200 and 300 gallons.  A Multnomah County HazMat crew assisted Corbett Fire in stopping the leak.