New York's trains are supposed to include wider doors to reduce boarding time, plus chargers and wifi to feed our screen addictions. One obvious downside: no longer will the (not quite) empty subway car during rush hour serve as a warning sign to steer clear and rush to the next car. Under the new regime, every subway car will be the poop (or pee, or vomit, or months of accreted body odor) car, because there will be only one subway car.