The Massachusetts Bay Trans­portation Authority moves hundreds of thousands of people across Greater Boston each day—thanks to a vast system of buses, trains, and ferries that depends on coordination among thousands of employees. In this storied transit system, history runs deep: The Green Line still passes through the country’s oldest subway tunnels, built beneath the Boston Common at the end of the 19th century. Yet the MBTA is remarkably willing to explore new approaches, too. That’s thanks in large part to a trio of MIT alumni: Katie Choe ’98, SM ’00; Melissa Dullea ’00; and Karti Subramanian, MBA ’17. Together, they’ve been helping redefine what innovation looks like in one of the nation’s longest-running transit systems. Choe in particular has been at the center of this push as the agency’s chief of staff since 2023, a position in which she took the lead in revamping organizational culture. She wrapped up her tenure at the T to become CEO of Virginia Railway Express (VRE) in January, but before leaving, she spoke to MIT Alumni News extensively about her role. Describing it as “owning everything and nothing at the same time,” Choe explained: “I’m here to make things happen. I find places where we have a sticky organizational knot that needs to be untied.” Dullea, the MBTA’s senior director of service planning, is in charge of the team responsible for planning and scheduling every bus route in the system as well as the Red, Orange, Green, and Blue Lines. Her group also determines where buses operate and adapts both train and bus service patterns as the region changes.