Chicago trains drive over flaming tracks

It's only to keep the switches from freezing. The straight, unswitched lengths of track do not need or use this.

So is Chicago an outlier? Plenty of other places get cold in winter, and have trains. How does the rest of the world keep the switches from freezing?

Probably worth noting that a few days ago, when this video was likely recorded, the daily temperature range in Chicago was -4F to 7F (-20C to -13C).

I think it's common. Here is a reference to a news article from 100 years ago, for a different location.

Chicago trains drive over flaming tracks (bbc.com)