Travelers flying out of Newark Liberty International Airport over the next several months should expect potential delays as construction continues on the airport’s new $3.5 billion AirTrain system, which will cause partial shutdowns of the existing service.

The new AirTrain is intended to modernize the system, improve terminal connectivity and handle increased passenger demand. It is scheduled to open in 2030.

Port Authority officials say work on the replacement AirTrain, which is being built in part around the current, aging system, will require some weekday closures. Starting Thursday, Jan. 15, the AirTrain route connecting the airport rail station to the terminals will be closed on weekdays from 5 a.m. to 3 p.m.

The first phase of closure is expected to last around four months, with the route briefly reopening beginning Memorial Day weekend on May 22. It will then close again between Sept. 30 and Oct. 30.

“What we have learned from our other endeavors is to get to that world class, you have to take some pain,” said Jim Heitmann, chief operating officer of the Port Authority of New York and New Jersey. “You have to make alternative service.”

Ralph D’Apuzzo, redevelopment program director for Newark Liberty International Airport, said the shutdowns are necessary for safety during construction.

“The segment will experience intermittent outages over the next two years,” D’Apuzzo said. “Since we’re beginning construction in this area, in order to maintain safe working conditions, during active construction near the existing train.”

During the closures, shuttle buses will replace AirTrain service along the route. Airport officials say the buses will run every four to five minutes, transporting passengers between terminals, the airport train station and portions of the AirTrain system that remain operational. Fares will remain unchanged.

Port Authority officials say to allow an additional 15 to 30 minutes for travel through the airport while the closures are in effect.