Metra repairs "pull aparts" in the tracks using flames. View Full Caption Courtesy Metra/Michael Gillis

CHICAGO — Metra has a really, really cool (well, hot) way of repairing its tracks.

Fire.

Metra, like many rail agencies in cold weather locales, put direct flames to its rails in the cold weather to help with repairs. ABC7 recently posted a helicopter video showing trains rolling through tracks while they are in flames. The video has more than 1 million views.

What it shows, said Metra spokesman Michael Gillis, are workers using fire to prep the tracks.

"Really cold" temperatures can cause the steel tracks to contract, shearing or bolts or creating small cracks or breaks called "pull aparts," Gillis said. Similarly, warm summer temperatures make the tracks expand and kink.

To fix pull aparts, workers have to heat up the steel so it expands, Gillis said. They typically do that by taking a length of rope or other material, soaking it in kerosene and then lighting the rope on fire along the rail they want to repair.

The next step varies depending on what will work best: Sometimes workers weld to fix the break and sometimes they have to rebolt tracks, said spokeswoman Meg Reile.

Watch ABC7's video to see what it looks like:

It's "not extremely unusual" for workers to have to fix the tracks that way, Gillis said.

"We are warming up the tracks so that we can make the repair, but it's not something we do in normal service to warm the tracks," Gillis said.

In fact, every time there's even the slightest crack or break it has to be fixed, Reile said. Train engineers inform Metra if they spot an issue and rail inspectors go over every side of the tracks daily — if not multiple times a day — in cold weather to look for problem spots, Reile said.

Metra will reroute or stop trains while the break is fixed, Reile said. Trains can also go over small cracks, but only if traveling slower.

"No trains were delayed while they were making that repair," Reile said of the ABC7 video. "We were able to route around it and no trains were delayed. For our customers, that's significant. They weren't waiting longer to get home because we had a repair. That's why we're trying to be on top of it."

Metra doesn't need to use fire to warm the tracks for normal use, Gillis said, though it does sometimes have to warm up railroad switches. Switches are the mechanisms that help trains move from one track to another.

To keep switches operational, Metra uses hot air blowers (kind of like hair dryers), electrified metal (like a curling iron) and gas flames (which look like a gas stovetop), Gillis said. Those keep snow and ice from building up along the switches.

If you're still trying to figure out why it looks like Metra's setting its tracks on fire, check out this video, which shows a similar process:

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