CHICAGO (Reuters) - Union Pacific Corp ( UNP ) said on Wednesday that Ferromex (FXE), the Mexican railroad it interchanges with, has resumed issuing permits for grain shuttle trains at the U.S.-Mexico border crossing at Eagle Pass, Texas.

FXE could not be reached for comment on Wednesday.

Pipeline issues are beginning to improve, Union Pacific ( UNP ) told Reuters in an email statement.

Grain shuttle train traffic between the U.S. and Mexico has been snarled in recent months as booming demand outstripped the system's capacity, creating heavy congestion and a growing backlog of loaded trains, agricultural export sources said.

Efforts are ongoing to clear up service interruptions at the U.S.-Mexico crossing at El Paso, Texas, Union Pacific ( UNP ) said. "Permits for El Paso will be granted once regular crossing cadence is established."

U.S. East and Gulf Coast port workers have gone on strike, holding up some imports of beef that restaurants and retailers increasingly rely on to make hamburgers due to limited domestic supplies, traders and industry members said.

This week, Berkshire Hathaway-owned BNSF Railway said it had resumed issuing permits for grain shuttles heading to Mexico.