Union Pacific will resume transporting oil by train on the Oregon side of the Columbia River Gorge sometime this week for the first time since the derailment in Mosier on June 3.  Union Pacific spokesman Justin Jacobs confirmed what he called “normal operations” to resume over the course of the week, including the transport of crude oil.  He added the railroad has an obligation to its customers and under federal law to transport various goods on a daily basis, including hazardous materials.  He added if customers deliver a crude oil tank car that conforms to U.S. Department of Transportation requirements, Union Pacific is obligated to transport the rail car to its destination.  Several government officials in Oregon and Washington along with environmental activists have pushed federal authorities to place a moratorium on oil trains through the region, saying they are too dangerous.  Meanwhile, Jacobs said a preliminary estimate of a diesel fuel leak from a train that stopped at Bridal Veil on Tuesday is about 200 to 500 gallons in size, and personnel are on the scene assessing what happened, with the locomotive being moved to an area where it can be better studied.  He added responders determined there was no impact to waterways.