U.S. President Joe Biden's emergency board tasked with helping major freight railroads and unions end a contract negotiation stalemate delivered its recommendations on Tuesday, a White House official told Reuters.

"The president is optimistic the report will provide a good framework for successful negotiations between the parties over the next 30 days," the official said, adding the recommendations were delivered to the White House and the parties.

Talks between major freight railroads, including Union Pacific, Berkshire Hathaway-owned BNSF and CSX, and unions representing 115,000 workers have dragged out for more than two years.

Biden appointed the three-member board in July to reduce the risk of a potential strike or lockout that could damage the fragile U.S. economy and choke supplies of food and fuel.

Railroads move everything from Amazon.com Inc packages to fuel oil and soybeans. Service shutdowns of any kind could send prices for necessities higher and upend battered U.S. supply chains.

Work stoppages are prohibited for 30 days following the issuance of the presidential emergency board (PEB) report to give the two sides time to reach a voluntary settlement. If employers or unions reject the board's recommendations, Congress can intervene.

"To avoid a national rail shutdown, it is in the nation's interest that the parties reach a prompt resolution," the White House official said.

The unions and railroad groups involved in the talks did not immediately respond to requests for comment.

Meanwhile, rail service at major U.S. seaports recently has suffered due to spreading supply-chain snarls and labor and equipment shortages.

"It is in the best interest of all stakeholders for the parties to reach agreements that provide our employees with well-deserved pay increases and prevent rail service disruptions," Union Pacific said in a statement.