The CTA concourse at O’Hare has four pairs of moving walkways — two from Terminal 1 (north) to the station, and two from Terminal 3 (south) to the station. (Terminal 2 is nearly in front of the station.) Let’s number these A, B, C, and D, north to south. When rebuilding the walkways, crews could shut B & C or A & D, thereby leaving one walkway in service in either direction. But… no. Last winter, when I was on a bunch of American (Terminal 3) flights, C & D were closed. This spring, when I have a bunch of United flights, A & B are closed. “Sprinting across the vast plains of terrazzo,” as the AIA Guide puts it, is no fun.