Local politicians, school department officials and hundreds of Tewksbury High students lined up on a cold and drizzly day to take part in a "topping off" ceremony which marks a major milestone in the construction of the new Tewksbury High School on Thursday.

A "topping off" ceremony is a construction-industry tradition with Scandanavian roots that celebrates the moment when the construction crew completes the highest structural point of a new building. It is believed to bring good luck to the construction crew and the occupants of the building once it is completed.

Superintendent of Schools Dr. John O'Connor addressed the large gathering near the construction site and pointed out that there are three significant events in a construction project such as this.

"The first is the ground breaking ceremony," O'Connor explained. "That's the day when everybody imagines what (the new) Tewksbury Memorial High School will look like.

"Today on the topping off ceremony we get to see what it looks like and we see the impressiveness of this building with  all of this steel," he added. "And I can't wait 15 more months from now, when we're going to have the "wow" event. That's when we'll do the ribbon cutting and we'll all be walking though the building and every corner we'll be turning around saying 'Wow, look at this.' It's going to be very, very impressive."

Tewksbury High Principal Dr. Patricia Lally hosted the ceremony, which was organized with the help of the town's High School Building Committee. State Sen. Barry Finegold, D-Andover, and State Reps. Jim Micelli, D-Wilmington, and Paul Adams, R-Andover, all addressed the large gathering, as did Katherine Craven, executive director of the Massachusetts High School Building Authority.

"People have made a real investment of time and effort to bring us to where we are today," said Micelli. "Someone said this was a bold step, with the economy the way it was (when the process was started). And it was. But this town has always shown its willingness to make an investment into education."

Students and dignitaries alike lined up to sign a ceremonial steel beam, which will be placed at the top of the structure. A second ceremonial beam was signed by the students in the Wynn Middle School, many of whom will be the first to attend the new high school for four full years.

"We are going to have a state of the art facility when all of this is done," TMHS principal Dr. Lally said. "Our kids are going to have opportunities, for technology, for sports, for theater,  that they don't have now.

"With the  new school comes a lot of pride," Lally added. "We're hoping it's going to mean that Tewksbury students will want to come to Tewksbury High School more than ever."