Of course it was bound to happen, and no doubt is happening more often than is reported, due to the lack of available testing in the US, compared to, say South Korea or Italy. The question is for me is, what form of transportation offers the best odds on staying healthy, planes or trains. I still think Amtrak wins: airports are occupied by many more people, at closer proximity, than train stations, and you have to show up farther in advance, which means more exposure to more people. Once you get on a plane, you're in closer contact with fellow passengers than on a train, so the odds of getting enough viral load to get sick are higher. The downside of train travel is that you're in contact with those other people for a lot longer. For me, I'm still sticking with my April cross-country Amtrak trip, though this could change as the coronavirus situation changes.