Regional freight railroad operator Genesee & Wyoming Inc. said Friday its traffic rose less than 1 percent in December, as growing metals and agricultural shipments offset lower shipments of coal and some other materials.

Last month's shipments rose 0.6 percent to 82,009 compared with December of 2010. Excluding added shipments from an acquired railroad, traffic fell 1 percent. That decrease was mostly due to lower coal shipments in Ohio and the Mountain West region. Mild winter weather and cheaper natural gas has decreased U.S. coal demand.

Metals shipments grew 32 percent, bolstered by rising Southern steel and scrap traffic.

Genesee & Wyoming said traffic in the last three months of the year rose 7.9 percent due to added shipments from an acquired railroad.

Genesee operates railroads in the U.S., Canada, Europe and Australia.