The attorney for the Lackawanna Plaza developers has filed a motion to allow his clients to intervene in the suit by a group of residents against the planning board and the township over the project’s approval.

The suit, filed by attorney Jay Rice on June 21 in Essex County Superior Court, alleges the planning board’s approval failed to consider — and is in violation of — the master plan, historic preservation ordinances, and parking ordinances of the township of Montclair. The suit filed by by A Better Lackawanna, LLC — an entity consisting of Montclair taxpayers and historic preservationists — and Greenwood LLC, a medical office at neighboring 1 Greenwood Ave.,has been amended to include 200 other residents as plaintiffs.

In May, the planning board approved plans by developers Pinnacle and Hampshire Cos. to build 154 housing units, a 29,000-square-foot supermarket and 111,726 square feet of office retail space at the 7.5-acre site of the former Lackawanna Train Station.

Developers Hampshire & Pinnacle Companies sought relief for the proposed 459 parking spots for the entire site, far less than the required 833. In order to make way for the parking, the plan also includes razing the mall, that since the 1980s, has encased the original train waiting platforms. Historians attempted to persuade the developers to save all of the historic elements of the 1913 station, including the platforms. They suggested the sheds be repurposed for the grocer and that the former Pathmark building be razed instead.

The suit also states that planning board members limited the time for public comment on the application by setting arbitrary time limits and imposing an arbitrary ban on those who were permitted to speak.

The developers released a statement on July 18 that the suit will only delay the opening of a supermarket in the Fourth Ward and would furthermore cost the taxpayers money.

Brian Stolar, president of The Pinnacle Companies, said the suit will cost the town legal fees and lost taxes on the project every day it is delayed, as well as jobs and affordable housing for Montclair residents.

The judge is expected to decide the motion filed by Tom Trautner on behalf of the developers on Aug. 16.

The resident’s suit seeks the reversal of planning board’s approval of the development, that the application be denied and reimbursement of counsel fees.