Montana Rail Link moved 109 cars Friday from storage in the Bitterroot to the Missoula yard, spokesman Jim Lewis said.
Lewis said MRL aimed to complete the move by early afternoon, with traffic delays at intersections of no more than 10 minutes.
"We don't think there's going to be excessive delay caused for the motorists," he said in the midst of the move.
MRL is moving the cars in response to the needs of customers, he said. Some of the cars also need to be scrapped, he said.
He said MRL has 380 cars in storage in the Bitterroot, down from a peak of some 600.
"But we've been moving cars out of there a little bit at a time over the last few months," he said.
In the near future, MRL will move another 113 cars to Missoula, although the timing isn't set yet, he said.
Then, MRL will have just 158 cars in the Bitterroot between Lolo and Florence, and he said it plans to move those along the Bitterroot River between Lolo and Missoula to get them out of view of the general public.
The cars were stored there following a 34 percent slow-down in coal shipments in 2016.