Stuff like the continued ADA station rollout, contactless payment, and signal modernization were things that he spearheaded. The trains in 2017 were an absolute shitshow, and he managed to turn it around. He wasn't a magic bullet—the MTA remains a terribly inefficient organization, and fact that Cuomo could effectively strip him of authority to undermine him demonstrates the limits of what he was able to accomplish—but the city would absolutely be worse off without his term here.