Jan. 31 (UPI) -- It's been so cold in the Midwestern United States that some have taken to fight the freezing temperatures with fire.
Flames have been spotted this week flashing along Chicago's Metra commuter rail line in an attempt to keep the trains moving smoothly during these frigid temperatures.
"One particular issue caused by winter weather is snow- and ice-clogged switch points, which can bring a train (or several) to a halt until the blockage is clear," Metra said on its website.
To prevent this from happening, Metra employs gas-fed heaters along its rail, so as to keep them warm and the switches clear of snow, Metra said.
"Anytime it's below freezing we're using these," Metra spokesperson Michael Gills told CNN.
Metra also uses a tubular heating system and hot air blowers, CNN reported.
Another issue that arises when temperatures drop that Metra solves by fire is something called "pull-aparts," which is when two rails separate at their connection due to the steel contracting in the cold.
"How Metra forces make repairs is by warming the metal up with fire until it expands and the two rails can be reconnected," Metra said on its Instagram account.
Prior to the installation of this system, maintenance workers filled what they called "smudge pots" with kerosene, which were then placed in between the track ties and then lit by hand.
"We all used to carry this stuff, I called it skunk oil," engineering director John Meyer said on Metra's website. "We poured it in a two-gallon can, poured it out, and threw a match in it, and it'd start a fire along all the rails. We're talking in the mid-'70s. Nowadays, you'd get in big trouble doing that."
However, despite having done away with the smudge pots, the present system can't be called safe either, Metra said, as the maintenance workers light the heaters by hand in order to control the flow of gas, which adjusts the size of the flame.
And for commuters worried that the flames from the tracks may cause diesel trains running above to ignite, rest assured: "diesel combusts only with pressure and heat, not open flames. Therefore, operating our locomotives and railcars over the switch heaters is completely safe," Metra said.