Grain merchants say the wild card for success or failure in moving more than 130 million tons of U.S. grain exports in the coming year will be "logistics," meaning barge and truck availabilities but especially railcars and diesel locomotives.

"Our main concern at this point would be how efficiently those trains move in and out of the export terminals," said Paul Hammes, a vice president of ag products with Union Pacific rail. "Getting the turn once the train gets into port is going to be the biggest variable for us."

The spotlight will be on the grain states west of the Mississippi River, which see commodity flows to West Coast ports and ethanol plants as well as flows into and out of Canada and Mexico and to the Texas and Louisiana Gulf ports.

Rail rates to ship grain for August, September and October have already spiked to highs last seen in the fall of 2007.

"You're talking about 25 to 30 cents a bushel cost in freight that wasn't there last year," said Christopher.

One question is whether exporters will pump up their wheat bids high to spark country elevators to move hard red winter wheat, which accounts for half the U.S. wheat crop.

"With rail costs what they are the country will make every effort to store every bushel some place. If those costs come down everybody will get in a big hurry to ship," Christopher said. "If they can't, you'll continue to have basis problems."

"For our railroad we anticipate full export programs for the PNW, Texas Gulf and Lakes," BNSF's Kaufman said. "We have committed the resources to meet this opportunity." (Reuters)