LYNN – The city has secured a $53.5 million state commitment to help pay for the new Marshall Middle School, two weeks after local voters approved borrowing money to help cover costs associated with the $92 million project.State Treasurer Steven Grossman in a statement Wednesday called the state School Building Authority?s vote in favor of the Marshall project “a down payment on the academic excellence of students in the city of Lynn.”Proposed school plans call for building the four-story school with a rooftop play field on vacant Brookline Street land bordering commuter rail tracks. City Inspectional Services Director Michael Donovan said construction is scheduled to start in spring or summer of 2014 and take place over two years.Voters overwhelmingly approved borrowing money to pay for the school, the first built by the city in 16 years, on Sept. 17, contingent upon an 80 percent state reimbursement.Not all Marshall costs, including initial project planning expenses and acquiring the land from a Marlborough developer and two residential property owners, are reimbursable and the state has a strict square-footage formula for computing reimbursement costs.School Superintendent Catherine Latham on Wednesday said the authority vote moves Marshall planning “into the project scope and budget phase.” Donovan said securing that approval meant providing state officials “with a lot of information about the methods we are using” to plan and build the school.Plans for replacing the 90-year-old existing school on Porter Street include organizing academic sections in the new Marshall into clusters where sixth through eighth grade students will study. The play field will be built on top of a building wing containing the gymnasium and cafeteria, and parking will be located at the building?s Empire Street end. A small courtyard will be centered behind the main building entrance located midway along the building?s length.Donovan said clay soil conditions on Brookline Street require extensive underpinning for the new school that, he said, will ensure that the sinking foundation at Classical High School will not occur in East Lynn.?The entire building will be supported on piles: There will not be another Classical out there,” Donovan said.The new Marshall will total 182,000 square feet, said Donovan, compared to Classical?s 205,000 square feet. About 1,100 students will attend Marshall compared to 1,300 to 1,400 attending Classical.