Toronto, January 31: With the polar vortex swirling over US states, some public service organisations have had to take extreme measures to tackle the effects of the extreme cold caused by bitterly cold winds. The city of Chicago which has been reeling under record freezing temperatures saw workers of its train transit system resort to setting the tracks on fire to prevent them from being damaged.

Flames were seen on the tracks of Chicago's Metra commuter rail system over the past couple of days as the city saw temperatures dip to -27 degrees Celsius. Along with this, a wind chill warning was in effect until noon on Thursday with wind chills as low as -50 degrees Celsius. Read: What Happens To The Human Body At -50 Degree Celsius and How To Avoid Hypothermia

To combat the effects of such extreme cold conditions, Metra rail explained that it employed a system of a series of underground gas pipes designed specifically to heat the train tracks. Flames actually come from gas-fed heaters that run alongside the tracks and keep them warm. This system is deployed to prevent the tracks from experiencing "pull-aparts." The extreme cold shrinks the tracks which are made of metal and the rails literally pull apart from each other, Metra said in a recent Instagram post. Heating the tracks with fire expands the metal until the two rails can be put back together again.

Metra rail deploys its crew members who work 12-hour shifts to monitor the flames. Trains are running on the tracks even while the flames are burning.

But to those seeing it for the first time, it is quite shocking to see trains running on tracks that are on fire. Metra rail says it's safe to run the trains over the flames because the diesel fuel in the trains "combusts only with pressure and heat, not open flames."

On its website, the rail organisation also recounts that in days of old when the gas-pipe system did not yet exist, the winter crew employed a far more basic system for heating the tracks. Workers carried “smudge pots" which was filled with kerosene, they would then place them in the spaces between the track ties and light them. This was all done by hand. “We all used to carry this stuff, I called it skunk oil,” said John Meyer, director of engineering for the Milwaukee District. “We poured it in a two-gallon (8 litres) 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.”

(The above story first appeared on LatestLY on Feb 01, 2019 01:12 AM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).