BRUNSWICK — After meeting with rail officials twice in July, opponents of a proposed $12 million train layover facility remain skeptical about assurances it won’t have a negative impact on their neighborhood.

At a Tuesday meeting, members of the Brunswick West Neighborhood Coalition repeated their call for rail officials to add extra mitigation efforts to reduce noise and pollution from Amtrak Downeaster trains that will move in and out of the layover facility planned at Church Road and Stanwood Street.

The meeting was the second of two advisory group meetings held in July by the Northern New England Passenger Rail Authority, with officials from the Maine Department of Transportation, Amtrak and the town.

Dan Sullivan, chairman of BWNC, said his group would like NNEPRA to find a way to remove particulate matter from diesel exhaust before it escapes the layover facility’s ventilation system.

Patricia Quinn, NNEPRA’s executive director, said the layover facility’s current design does not include any features to filter diesel emissions, but said her board would consider the request.

Members of BWNC also more details about when trains are expected to make noise in and around the layover facility.

NNEPRA and Amtrak had provided BWNC members an operations report at a July 9 meeting that outlines most cases in which Downeaster trains would make noise, move or idle. But the abutters remained unconvinced they weren’t getting all the answers.

Fred Fournier, an Amtrak official, said it would be hard to provide an exact illustration of when a train is expected to make noise every day of the year, because some actions, including the cutting and transferring of train cars, don’t always happen at the same time.

BWNC members also repeated their skepticism about previous reports showing that a layover facility next to their neighborhood would not have significant air quality or noise impacts. But Quinn said the U.S. Federal Rail Administration would ultimately decide in its environmental review if there are any problems.

While another advisory group meeting is scheduled for Aug. 20 at Brunswick Station, the town is also planning its own workshop on the layover facility, tentatively set for Aug. 13.

Town Councilor John Perreault said the workshop will include a presentation of the layover facility design by Consigli Construction of Portland, and discussion of related issues, including the possibility of measures the town can take to institute quiet zones at all of its rail crossings.

Dylan Martin can be reached at 781-3661 ext. 100 or dmartin@theforecaster.net. Follow him on Twitter: @DylanLJMartin.