A proposal to push back high school start times to let more St. Paul students sleep longer received a long-awaited boost on Tuesday.

The school board voted 4-3 to order up a plan for start time changes in 2018-19 that would take into account the “health and academic best interests” of students.

While stopping short of actually guaranteeing changes, the board’s actions represented the strongest move yet to align start times with teenage body rhythms.

District students would have the chance to reap the benefits of sleep and start time research conducted locally and nationally. At no time in St. Paul’s frustrating two-year debate on the issue has the board taken the step of specifying a date by which it wants changes made.

But the move won’t be easy. One scenario pitched to accomplish a new 8:30 a.m. start for middle and high school students would call for thousands of elementary students to be shifted into a 7:45 a.m. start time that has proved unpalatable to many parents.

Board Member Chue Vue, who joined John Brodrick and Jeannie Foster in opposition, also took issue with the possibility of the district having to spend $2 million to $4.4 million to change its bus system to accommodate the start time changes, saying that money could be put to better use elsewhere.

Board Member Steve Marchese argued there were few things a district could do with as high a documented level of success, and he believed the district could explore creative ways to work through challenges.

“It is important that we’re taking the time to do it right,” he said.

The district also is worried about losing students to other districts and charter schools because it no longer could have an elementary option in the 8 o’clock hour.

The inability to increase enrollment has been an ongoing concern in the state’s second-largest district. A report presented Tuesday showed that the district had 493 fewer students on Oct. 1 than it projected for 2016-17: 36,954 compared with 37,447.

The board struggled this year to fill a $15 million funding gap for 2016-17 and could face a larger $24 million deficit for 2017-18.