Contractors have finished only about a quarter of the $10.5 million in repairs planned for 233 miles of state-owned railroad tracks between Millinocket and Madawaska, but freight customers should already be seeing some marked improvements, state officials said this week.

About half of the 7,500 feet of rail replacement has been done, and 11,000 of the planned 50,000 ties have been replaced since August. Work was recently suspended due to weather conditions, said Nate Moulton, director of the Maine Department of Transportation’s rail program.

“We really didn’t get under way until August,” Moulton said earlier this week. “They got some of the worst areas taken care of and next year we will really get into it. Once you get frozen ground, there’s not a lot you can do to finish the work until it thaws again.”

The U.S. Department of Transportation is funding the repairs with a $10.5 million grant. Work will resume next year when weather conditions permit and carry through until it is finished sometime in the fall, said Ted Talbot, spokesman for the Maine Department of Transportation.

The line’s previous owner and rail carrier, Montreal, Maine & Atlantic Railway, sought federal approval in February 2010 to abandon the tracks, citing losses of $4 million to $5 million annually. Maine taxpayers saved the rail line in June 2010 by approving $7 million in borrowing to buy the tracks. They were purchased by the state last Jan. 14 for $19.1 million.

While still functional, the tracks had fallen into disrepair, with long stretches where safety concerns prohibited train speeds greater than 10 mph. The disrepair, plus a lack of product to haul, caused MM&A to miss deadlines or not run enough trains to make money or satisfy customers, rail officials said.

Another freight service, Eastern Maine Railway, replaced MM&A as the route’s primary hauler in April and customers said they saw some improvement then.

Moulton said contractors concentrated their efforts on the worst or most worn sections of track on the 233-mile line, which state leaders regarded as critical to the survival of the 22 large-scale manufacturers that use it and the thousands of northern Maine workers that the manufacturers employ. The repair or replacement work has improved some track speeds and, thereby, the efficiency of the rail service itself, he said.

“There are still some [10-mph areas] out there, but we have cleaned up some of them,” Moulton said. “We are under way. We got a fair amount done.”

Transportation officials had hoped to start the work earlier than last August, but delayed it when suppliers had difficulty getting enough railroad ties and rails for the job, Moulton said.

Contractors and transportation department workers will continue to stockpile supplies over the winter, he said.