The Federal Aviation Administration has granted environmental approval for a $2 billion project to replace Newark Liberty International Airport’s aging and problem-plagued monorail.

The air train was built in 1996 and has required regular and costly maintenance in recent years. In 2014, it had to be taken offline for repairs for two months, forcing travelers to take shuttle buses.

The Port Authority of New York and New Jersey says it hopes to begin construction on the monorail in mid-2022 and have it ready for service by 2026.

“This decision is a key step in replacing the long-outdated AirTrain,” Gov. Phil Murphy said in a statement. “New Jerseyans and travelers deserve a world-class transit system at Newark Airport, and we are much closer to attaining that reality with the FAA’s latest action.”

About 2 million people per year rode the train during pre-pandemic times.