(CNN) - A cold, arctic outbreak is hitting Chicago.
There's a threat of hypothermia for people and pets, but even trains are affected by the freezing temperatures.
Rail tracks were set on fire to keep them running.
Chicago resident Wade Horvath shared video Wednesday on Instagram from inside a Metro rail.
"You know it's cold in Chicago when CTA lights the train tracks on fire to keep the switching mechanisms from freezing."
The National Weather Service forecasts dangerously cold wind chills as low as 60 degrees below zero in the area through Thursday.