PORTLAND – A tentative agreement to end a strike against Canada’s largest railroad is good news for Mainers who heat their homes with propane, but it won’t bring an immediate end to tight propane supplies, officials said Sunday.

The United Transportation Union encouraged its 2,800 workers to begin returning to their jobs Sunday, a day after a tentative agreement was reached with Canadian National Railway.

“That can only be good news for us, even if it takes them a couple of weeks to get everything flowing right. It shows us there’s light at the end of the tunnel,” David Farmer, spokesman for Gov. John Baldacci, said Sunday.

Maine depends on rail shipments for 60 percent of its propane, and supplies quickly became tight during the Canadian National strike.

There were no reports of anyone going without heat, but Maine propane dealers had to take steps to control their inventory either by making partial deliveries or skipping homes whose tanks were more than halfway full.

“It’s still very tight. Inventories in Maine have been completely depleted,” Jamie Py, president of the Maine Oil Dealers Association, said Sunday. “Rebuilding those inventories is going to take time.”

Propane, liquefied petroleum gas, ranks behind heating oil and natural gas for heating homes in New England, but tens of thousands of homeowners use it for everything from heating homes to running cookstoves and clothes dryers.

In Maine, more than 25,000 homes, roughly 5 percent of the total, use propane as their primary source of heat. Businesses including fast-food restaurants, big-box retail stores, nursing homes and hospitals also use propane.

Although rail disruptions were the primary cause of the shortages, bad weather contributed by delaying two ships in Newington, N.H., and Providence, R.I., officials said. And a pipeline rupture temporarily disrupted supplies last week to a pipeline terminal in Selkirk, N.Y., another source of New England’s propane, Py said.

Maine officials were able to secure 3 million gallons of propane from the latest barge, which arrived over the weekend in Providence, Farmer said.

As for rail service, Canadian National workers who left their jobs Feb. 10 have been encouraged to return to work pending a formal vote on the tentative agreement. They’re asked to remain on the job until the ballots are counted on March 26.

It was unclear Sunday when regular propane shipments would resume. But both Py and Farmer were hopeful.

“Once the rail cars start coming in more regularly, that would at least solve the immediate problem,” Farmer said. By the time the ballots are counted on March 26, the worst of the winter weather will be over, he added.