What is an arcing insulator?

The Federal Transit Administration has ordered emergency repairs for three critical track locations within the Metro transit system.

There have been a lot of recent arcing insulator incidents on the tracks of the rail system and federal officials said they are requiring these repairs "to reduce the risk of smoke and fire events and to ensure the safety of passengers and employees."

But what does an insulator actually do?

"If you have one electric conductor, electric conducting metal for instance, and another on the other side, if you don't want any current to go between this one and the other one, you put an insulator in between," said Dr. Samuel Lakeou, a professor for the Department of Electrical Engineering for the University of the District of Columbia.

According to Metro, an arcing insulator is an insulator along the third rail that may be giving off sparks or smoke.

Dr. Lakeou said insulators can sometimes be faulty.

"At times, aging is a problem," he said. "Sometimes they get oxidized because of the deposition on top of them. They create some arcing."

Lakeou leads the university's Electrical Engineering Department where students' senior project could include submitting recommendations to Metro on how to fix their mounting problems.

Lakeou said the issue for Metro is an aging system that has been neglected for so long that it will take a lot of work and maintenance to get it back on track.

"The ones that we are seeing here are systemic problems that need to be fixed at some point, and I think WMATA will have to find a way to schedule some way of looking at every part of the lines," said Dr. Lakeou.

He said that would require a shutdown lasting longer than just one day.

On Tuesday, Transportation Secretary Anthony Foxx threatened to shut down Metro if it doesn't follow the FTA's directives.

Last year, students at UDC submitted recommendations on how to fix Metro's escalator issues. We are told some ideas were used.