What happens when it's so cold in Chicago that CTA rails crack?

How cold is it in Chicago?

So brutally cold that it can crack steel rails.

And what does the CTA do about that?

They call in their “protectors of the railroad.”

That’s the team of hundreds of workers that the transit agency says is ready to repair any rail cracks caused by the subzero temperatures gripping the city.

"Our job is just to keep the train running," Bill Costagliola, general manager of Track and Structure Maintenance at CTA, told the Chicago Sun-Times. .

For minor cracks, crews can put on a pair of joint bars — a 36-inch piece that connects the tracks — as a temporary fix. But for bigger cracks, like one that was found Jan. 14 on the Red Line near the Cermak-Chinatown stop, the section of the cracked rail needs to be cut out and a new section needs to be installed.

Repairs can take anywhere from one to two hours, depending on the severity of the crack.

Typically, any "vertical cracks that are no wider than a fist" are safe to travel on at reduced speeds before repairs are made, according to the infrastructure officials.

"Generally, anything straight up and down to a certain width is OK," Costagliola said. "Anything that moves diagonal or going along the web of the rail, that's really compromising [rail] integrity."

"The last thing we want our passengers to do is have to evacuate their train due to a track issue and now they're sitting on the platform when it's subzero degrees waiting on that next train," Costagliola said.

‘How the rail reacts is how we react’

As wind chills as low as 28 degrees below zero hit the city in recent days, roughly 200 CTA maintenance workers were available during business hours and 40 workers will be on watch on the overnight shift to repair any issues on the 265 miles of track they oversee.

Costagliola said the agency is prepared to do "whatever we have to do to make those repairs as quickly as possible."

In the days before the polar plunge hit, track inspectors walked the tracks looking for stress fractures in the rail expansion of joints and joint bars that have come apart and gaps in the rail among other defects.

When temperatures drop 20 to 30 degrees — like what happened over the weekend — rails begin to expand and contract.

The agency anticipates more rail cracks during the winter season and will brace for additional rail troubles when the temperature reaches around 10 degrees.

But their preparation — including the use of emergency vans ready to fix any track conditions — is also affected by "how the rail reacts to the weather."

"How the rail reacts is how we react to having those emergency vans," Costagliola said.

When a cracked rail is found, Costagliola and his team are notified before dispatching the anomaly to roadmasters, who then work with track personnel to fix the rail while management determines if service can continue at normal speeds or speed restrictions of 6 to 15 mph during repairs.

"Our first thing is ensuring the safety of our customers as well as personnel," said Lenny Romano, vice president of infrastructure maintenance. "If it's obviously a major crack, we don’t want to run a revenue train with our customers on it."

"You'd be hitting that bump pretty hard," Romano added.

When fixing a rail crack, Costagliola says it's important to "zoom out and see how other track conditions will affect the repairs."

Both new and worn CTA rails are at risk of cracking in cold temperatures, according to Costagliola and Romano.

"It all depends on the rail itself and the elements that it's in," Costagliola said. "If we have pondage where there's water constantly freezing on our tie plates and the rail itself, that adds wear and tear and it impacts the lifespan of that piece of rail."

Romano and Costagliola stressed the importance of the work done by maintenance crews from inspectors to engineers to the crews on the ground making the repairs, especially in extreme cold.

"They protect the railroads," Romano said. "Without them, [trains] wouldn’t be able to run.

"They're working late at night [or] in the wee hours of the morning," Romano added. "You don’t see them, but they're out there."