CHICAGO () - When temperatures drop to bone-chilling levels like we’re experiencing now, railroads use open flames to keep the trains moving.. According to Metra spokesman Michael Gillis, they’re using natural gas to heat switches. “It looks like the tracks are on fire, but what it is, there are gas burners next to the switches, and we light them to keep the switches warm, so the switches can move,” said Gillis. “If they freeze up, then our trains can’t change tracks and that leads to congestion…It’s really essential to keep the switches operational so that we can keep our trains...