Construction continues to ramp up at Baxter International’s $1 billion manufacturing campus on the Newton-Walton county border, and a handful of senior officials toured local media around the sprawling worksite Tuesday. The first building is under construction and is scheduled to be completed in late 2014, with the rest of the campus to follow in 2015. However, production isn’t scheduled to begin until the first quarter of 2018, as the new pharmaceutical plants must go through a complex inspection by the U.S. Food and Drug Administration and other federal and state agencies.