A polar vortex that dipped deep into the US set new low temperature records while stranding travelers on trains and in airports, officials reported on Tuesday. In New York City, it was four degrees in Central Park, breaking a record of six degrees set in 1896. Temperatures plunged below freezing in all 50 states on Tuesday as an arctic blast made its way from Canada into the Deep South of the United States. Authorities blamed at least 15 deaths on the cold, including 11 from traffic accidents and two from hypothermia. The record cold strained electric grids in many areas, officials said, including that provided in the South by the Tennessee Valley Authority. Five hundred people were left stranded in snowdrifts on three Amtrak trains overnight in northern Illinois, an Amtrak spokesman said. More than 2,300 flights were canceled within, into or out of the US on Tuesday morning, officials said in press remarks. Ships also ran into trouble, and the US Coast Guard Cutter Hollyhock had to break through ice in Lake Michigan.