An attorney representing a group of abutters who oppose a city-approved plan for 72 units of affordable housing next to Shawmut station has filed a lawsuit for their cause in a special session of the Suffolk Superior Court.

Julie Barry, an attorney with the firm Prince Lobel, told the Reporter that the filing names the Boston Planning and Development Agency (BPDA), Trinity Financial, and the Fitzpatrick Brothers as defendants. Barry, noting that she represents four abutters, Rachel Kemper, Eric Thorsen, Anthony Brown, and Ana Teixeira, said her clients don’t object to the idea of affordable housing, but rather to the scale of this project in relation to their own properties.

The suit marks the third legal action filed to challenge the BPDA decision in November to approve the project on the Fitzpatrick site at 150 Centre St. The other two suits have been brought by the Epiphany School and by another neighbor, Andrew Saxe.

Barry said the suit she filed challenges the BPDA’s designation of the proposal as a 121A project – often given to projects considered “blighted” areas. Another distinction of the Barry-led suit: She wants their complaint be heard in the Business Litigation Session of Suffolk Superior Court. She said her clients are “examining all their rights” while noting an issue of disputed property along the existing fence line that is not officially part of the suit.