No, this Chicago fire is not one to be nervous about ― but it does look really cool.

Social media has been entranced and a little concerned over viral images and videos of Chicago train tracks on fire as the city deals with record low temperatures this week.

But the videos aren’t as wild as they look. In fact, they’re completely intentional. Crews for Metra, the Chicago-area commuter rail, are fighting ice with fire to protect train tracks during the polar vortex deep-freeze.

During extreme winter weather, crews use the flames to prevent or repair steel tracks that contract when exposed to quick drops in temperatures. The cold can lead to cracks forming and rails separating, creating a risk of derailments. Heat causes the rails to expand again.

Snow and ice can also clog track switches, which control the rails Metra trains run on. If a switch is clogged, trains have to come to a halt until it’s cleared, causing major delays.

The tracks themselves are not on fire. Instead, Metra uses a gas-fed system to release flames that run next to the rail, generating heat in areas where switches would make contact. Metra spokesman Michael Gillis told the Chicago Tribune that crews use the fire system in normal winter weather too, but it stays on when temperatures dip below 32 degrees.

Chicago is so ridiculously cold that the railroad tracks need to be on fire to keep the trains moving.https://t.co/sALHCcAias pic.twitter.com/qN8CCzkSX7 — Jalopnik (@Jalopnik) January 30, 2019

The polar vortex has hit the Midwest with double-digit subzero temperatures. In Chicago, mail carriers are staying home and about 1,700 flights have been canceled as the city faces wind chill factors as rough as 55 below zero. On Wednesday, Metra reported major delays for some trains and suspended one of its lines for two days.

“Will some new technology be developed to better clear the ice dropped by railcars and locomotives? The answers remain unclear,” a Metra press release said. “But one thing is certain. Metra will continue to pit fire against ice to keep trains rolling.”

Chicago is so cold that it’s setting the train tracks on fire so they can run smoothly. Chicago is metal as fuck. pic.twitter.com/zbs4d0YVts — Sid (@sidneyraz) January 30, 2019

Chicago is BAD ASS.



Lighting the tracks on fire so they don’t freeze, to keep the city moving is next level municipal services. #Chiberia pic.twitter.com/gnz2eEQmtA — Stephen Punwasi (@StephenPunwasi) January 30, 2019

I'm just gonna show ppl this video whenever anyone asks me how cold it gets in Chicago https://t.co/HKS6k8a1n0 — Brandon Garcia (@bgarcia2195) January 30, 2019