The Maine Department of Transportation is shortchanging funding for a study on a proposed passenger rail line linking Portland and Lewiston-Auburn, a Democratic lawmaker from Lewiston says.

But the department says the amount is based on department estimates and is sufficient to fund the study.

Rep. Jared Golden said Thursday that Department of Transportation will issue only $250,000 to fund a service plan to link Amtrak’s Downeaster and the two cities, even though the Legislature approved $500,000 for the project in the 2016 state budget. The funding allocation includes $50,000 in matching funds from each of the two cities.

The possibility of extending passenger rail to Lewiston-Auburn has been discussed for years, and the state has funded a previous study examining the proposal. A service delivery plan would determine whether the return on investment from the service justifies the millions of dollars needed to get the train up and running.

Having a service plan in hand indicates a “shovel ready” project and may make the state competitive for federal funding, Golden said.

But without the full allocation, the final service plan may not be sufficient for attracting funding, he said. The cities of Lewiston and Auburn agreed to contribute matching funds with the expectation that the full $500,000 would be allocated, Golden said.

“I recognize the fact that (the study) could come back and say the return doesn’t justify the investment,” he said.

“It feels unfair, like our communities are being shortchanged. The budget is public law, and DOT has an obligation to follow that law,” Golden said.

The study will focus on the market demand for passenger rail to Lewiston-Auburn, the economic benefits of the proposal, a possible train schedule, necessary equipment and infrastructure, and funding mechanisms for the service.

Although the Department of Transportation will fund the study, it will contract with the Lewiston-Auburn Economic Growth Council to submit the request for proposals and set up the process.

In an Aug. 17 email to Multimodal Planning Division Manager Susan Moreau, Growth Council President John Holden questioned the discrepancy between the $500,000 allocated in the budget and the $250,000 that the department approved to fund the study. The growth council has not finalized a contract with the state.

In an email response, Moreau said there was $150,000 available from the state’s General Fund account and $50,000 each from Lewiston and Auburn.

“I think we should be able to get a good product with that amount,” Moreau wrote.

On Thursday, spokesman Ted Talbot said the department based its estimate on the proposed scope of work of the study.

“From our decades of experience, of project analysis, we believe there is a lower cost for the scope of work than was allocated,” Talbot said. If the cost of the study turns out to be higher than estimated, additional funding could be used, Talbot said.

Auburn Mayor Jonathan LaBonte said Thursday that he was glad to see the Department of Transportation move forward with the proposal.

The study’s scope of work seemed sufficient and he didn’t see the value of debating funding levels, he said. LaBonte, along with Golden, is a member of a stakeholder advisory team for the study.

“I don’t see the value of getting into an argument about what did the Legislature intend to appropriate and should we spend it all,” LaBonte said.