North Bay cargo trains may be closer to returning to the Northwestern Pacific Railroad now that a major obstacle has been removed.

U.S. transportation regulators have ruled that the North Coast Railroad Authority doesn't need commuter rail's okay to reopen the freight line.

That means the Federal Railroad Administration can now inspect repairs on a 62-mile stretch of track between Napa County and Windsor. "It's a significant step," NCRA director Mitch Stogner said Monday.

But NCRA still needs a joint operating agreement with Sonoma-Marin Area Rail Transit, the commuter rail agency that owns the tracks.

NCRA hopes to begin freight service on the segment early next year, Stogner said, which will provide a lower-cost alternative for shippers and take truck traffic off Highway 101.

Federal regulators closed the route in 2001 after storm damage made it unsafe for trains. NCRA is spending $68 million to fix the southern end of the railroad. Last month it said repairs were complete and ready to inspect.

Tracks, bridges, signals and crossings must pass inspection before federal officials lift their embargo.

But the plan hit a snag when a Federal Railroad Administration official ruled SMART must join NCRA's petition to reopen the line.

SMART directors said last month they wouldn't support the request until the two agencies agree on joint operating rules. SMART plans to start running commuter trains over a portion of the railroad in 2014.

NCRA appealed the federal ruling, and the railroad administration reversed its position last week. In a letter Friday, the federal agency said SMART's support isn't needed for the freight closure to be lifted.

But NCRA still must resolve any disputes with SMART before freight trains can operate, the agency said.

Negotiations over the track-sharing agreement are snarled on various issues.

SMART officials haven't received last week's letter and aren't prepared to comment, spokesman Chris Coursey said Monday.

Negotiations over the track-sharing agreement are snarled on various issues, but Stogner said NCRA and SMART "have made significant headway" on the agreement since last month.

NCRA also must adopt an environmental study of the freight service and tweak a lawsuit settlement with Novato, which sued over the trains in 2007, he said.