ROCKLAND, Maine — Two proposals were submitted to the state to operate the railroad line that runs from Brunswick to Rockland.

The identities of the two bidders are not yet being released by the state. The deadline for bidders to submit proposals was Thursday.

Maine Eastern Railroad has run the line since 2003.

Maine Eastern Railroad carries freight year-round and a limited passenger excursion service during the summer. The company receives no state subsidy and is required to maintain the tracks.

Nathan Moulton, director of the rail program for the Maine Department of Transportation, said earlier this year that the requests for proposals were sought to determine what interest there is in continuing freight transportation and perhaps expanding passenger service on that stretch of line.

On Thursday, Moulton said two proposals were received. DOT spokesman Ted Talbot said no information about the proposals or who submitted them would be released until a contract is awarded.

Moulton said earlier this year that any regularly scheduled passenger service to connect Rockland to Brunswick would likely require a state subsidy to an operator. Moulton said the department wanted cost estimates from bidders on the amount of subsidy that would be needed.

Maine Eastern Railroad General Manager Harmony Llanto declined to comment Thursday on whether the company submitted a proposal. Earlier this year, Llanto said the company would submit one.

The line has been operated for freight traffic since May 1990, five years after Maine Central Railroad abandoned the spur. The state spent $30 million in the early 1990s to upgrade the tracks to be able to handle passenger trains, which resumed running on the Rockland line in 2004.

Passenger service during the past 10 years has been limited largely to summer excursion trips. The amount of traffic peaked at nearly 19,000 people in 2008, according to prior statements by Maine Eastern Railroad.

The largest source of revenue for Maine Eastern Railroad has been its freight service, and Dragon Products is by far its largest customer.

Another customer of Maine Eastern Railroad is Dica Perl Minerals, formerly known as Chemrock, on Buttermilk Lane in Thomaston. Maine Eastern Railroad also does some business with Bath Iron Works.