[custom_adv] They let trains that look too crowded pass by. If they decide to board, they search for emptier cars to ride in. [custom_adv] Then they size up fellow passengers before picking the safest spot they can find to sit or stand for commutes sometimes lasting an hour or more. [custom_adv] This quiet calculus is being performed daily by people who must keep working during the coronavirus pandemic and say the social distancing required is nearly impossible to practice in the enclosed spaces of public transit system. [custom_adv] The Centers for Disease Control and Prevention says that people should stay six feet (two metres) apart. [custom_adv] But even though ridership has plummeted in the city, making jam-packed trains and buses the exception rather than the rule, passengers aren’t always guaranteed even six inches (15 centimetres). [custom_adv] The virus has also taken the lives of 41 employees of the Metropolitan Transportation Authority, which runs the city’s buses and subway as well as many commuter trains. [custom_adv] In London, where ridership is down as much as 93 per cent from the same point last year, images posted on social media have shown some trains crowded at rush hour since fewer are running because of staff illnesses. Fourteen London transport staff have died from the virus, including eight bus drivers. [custom_adv] The challenges aren’t unique. In the city, where at least three transit workers have died from COVID-19, the Southeastern Pennsylvania Transit Authority said it will move to a “lifeline” service Thursday, closing some stations and limiting rail and bus service to core routes. [custom_adv] London, Paris and South Korea have also struggled to keep public transport running.