A portion of Union Station in which a woman was hit in the head by falling concrete has reopened after minor overnight repairs were completed, according to Metrolinx.

Emergency crews were called to the Bay West Teamway shortly before 6 p.m., according to the official Union Station Twitter account.

Shortly before 6:00 p.m this evening, a person was injured while walking inside the Bay West Teamway at Union Station. Paramedics transported her to the hospital. We wish her a full and fast recovery. 1/4 —@unionstationTO

Paramedics transported the woman to hospital with a reported head injury.

The teamway was closed for most of the night as engineers from Metrolinx, which runs GO Transit, and the City of Toronto, which owns Union Station, investigated. It reopened early Friday.

"Some minor concrete scaling and repairs were made," Metrolinx spokesperson Matt Llewellyn tweeted Friday morning.

"As is always the case, [we] will continue to monitor the Teamway, and out of an abundance of caution have ordered another thorough inspection in the coming weeks."

Metrolinx also pledged to assist in an investigation into what happened.

"We wish the woman who was injured last night a full and fast recovery," Llewellyn tweeted.

Toronto Mayor John Tory, out campaigning with just over a week to go until the municipal election, said Friday that "many precautions" have been taken during ongoing renovations at Union Station to ensure the safety of everyone who passes through the facility.

"Obviously in the wake of this incident we have to redouble our efforts and inspect it again. It's a big construction project," Tory told reporters. "These are very sad things to happen to cause injury to anybody but we've now got to just make sure it's absolutely safe and I'm sure that's what the Metrolinx people will be doing."

Union Station is the country's busiest transit hub, serving 65 million passengers each year. That figure is expected to jump to 130 million by 2031.

To accommodate the growing number of commuters who move within the station's walls, a major revitalization project is underway that has left it a dusty, confusing construction zone for the last number of years.

Earlier this year, a report from city council said the $800 million project will be over budget by more than $22 million. Construction began in 2010 and was initially scheduled to be completed in 2015, but repeated delays have kept work going through this year.

Nadia Hassan, who was travelling through the station Friday morning, said she saw the aftermath of the incident Thursday night. She saw blood running down the woman's face and on the floor.

"I was just thinking about how often we just go through this and it could have been anyone, it could have been anyone, and she just happened to be walking at that moment," Hassan told CBC Toronto.

The station was also hit by repeated flooding during heavy summer rainstorms.