Carol Glover, with sons Marcus Glover, left, and Anthony Raymond "Ray" Glover in 2014. (Courtesy of the Glover family )

Marcus Glover still has his mom’s phone number programmed into his cellphone.

It reminds him that even though she’s gone, she is still very much with him. Same with the texts and emails that he rereads for encouragement when he thinks back to last January, when the late-night knock at the door of his D.C. home changed his life.

Glover and the Washington region mark a grim anniversary Tuesday. One year ago, on a drizzly Monday afternoon, a Metro Yellow Line train headed for the Pentagon stalled in a tunnel just outside the busy L’Enfant Plaza station and was engulfed by noxious fumes. Glover’s mother, Carol I. Glover, 61, died of respiratory failure due to smoke exposure, and scores of others were sickened in the calamity.

The fatal incident would be the first in a series of system breakdowns last year that led to the resignation of the transit agency’s chief safety officer and an unprecedented federal takeover of safety oversight of Metro’s rail operations. On Monday, federal officials announced a stepped-up effort in their oversight of the nation’s second-busiest subway system, saying they will shift from periodic to daily inspections of Metro’s rail operations.

Marcus Glover talks about his mother on Monday, the day before the first anniversary of her death in a Metro accident. (Bill O’Leary/The Washington Post)

Metro General Manager Paul Wiedefeld, who took over the beleaguered agency in November, called the anniversary a “solemn day.”

“It’s a reminder to all of us in the agency of how serious our business is and how important it is for us to always think of the safety part of what we do,” he said in an interview. “This is something that cannot happen again.”

In a full page ad published Monday in Express, Wiedefeld sought to reinforce that message.

“As the new CEO, I started the job with a mission of rededicating Metro to safety, improving service reliability and getting our financial house in order,” he wrote in the open letter to Metro riders. “In the area of safety, the first executive I am recruiting is a new Chief Safety Officer, responsible for day-to-day oversight but more importantly, reinforcing a stronger safety culture throughout Metro.”

Even with additional scrutiny and a new leader in place, those who follow Metro say that a change in culture will not come overnight.

Carol I. Glover, 61, died of respiratory failure due to smoke exposure in a January 2015 incident on a Metro Yellow Line train. (Courtesy of the Glover family )

Therese W. McMillan, acting administrator of the Federal Transit Administration, whose agency took over safety oversight of Metrorail, emphasized that, ultimately, it is Metro and its management team that must take responsibility for the system.

“Although FTA is fulfilling a critical safety oversight function, responsibility for performing the actual work of making Metrorail safer for passengers and employees rests squarely on WMATA,” she said.

There is much work to do. A series of reports that followed the 2015 Yellow Line incident found that many of the same factors at play in the 2009 Red Line crash that killed nine people and injured at least 80 others — a lack of communication, gaps in maintenance and a lack of strong safety oversight — may have contributed to the Yellow Line calamity.

“After the [Red Line crash], we heard Metro was changing, but clearly it had not,” Sen. Mark R. Warner (D-Va.) said Monday.

Added Rep. Gerald E. Connolly (D-Va.): “The decline in a culture of safety, the decline in customer service, the decline in efficiency and competence has come over a long period of time. It will not be reversed immediately.”

The National Transportation Safety Board is investigating the cause of the fatal Yellow Line smoke incident. The NTSB has issued a series of critical recommendations for Metro as part of its preliminary investigation, but its final report is not expected until this spring.

Metro officials, however, said that in the year since the incident, they have moved aggressively to address safety lapses and shortcomings identified internally and by outside watchdogs.

For example, the initial investigation by the NTSB found that two of the six fans designed to push smoke away from the train did not work, and those that did were incorrectly deployed on Jan. 12, 2015, and pulled smoke toward the stuck train instead of away from it.

As a result, Metro has reexamined its tunnel ventilation system, and officials said they have fixed anomalies in 13 fans. All ventilations shafts now have working fans, the agency said. Metro said it also has retrained controllers in its rail operations control center on how to operate the tunnel ventilation system.

In addition, Metro said the agency has accelerated efforts to install safer “low-smoke” power cables throughout the rail system. The newer cables emit fewer noxious fumes if they start to burn, unlike the older cables located in the section of the tunnel where the L’Enfant Plaza crisis occurred.

The NTSB has said that the smoke resulted from heat and melting caused by a malfunction of electrical components on tracks in the tunnel just south of the L’Enfant Plaza station.

Even as Metro has moved to make fixes, problems have continued to dog the system.

Last week, two cars of a Green Line train came apart as they approached the Navy Yard station — a rare but troubling occurrence. Wiedefeld said the investigation into that incident is continuing.

While no one was injured when the two trains separated during the morning commute, Rep. Barbara Comstock (R-Va.) said the incident is another example of the importance of holding Metro’s leaders accountable and ensuring that they follow through on actions they say they will take.

“We just have to stay on them and not let up,” she said.

For the Glover family, whose $50 million lawsuit against Metro is pending in federal court, the most important outcome of the tragedy will be a transit system that is safe for all of its riders. This suit is one of many that have been filed against Metro. The Glover family’s lawyer said he is representing 12 other passengers who were aboard the train and suffered injuries that range from mild smoke inhalation to serious lung damage.

Lawyers from the firms Cohen & Cohen and Ashcraft & Gerel said they plan to hold a news conference Tuesday to announce at least 80 additional lawsuits in connection with the incident.

In the year that has followed Carol Glover’s death, the family has celebrated many happy milestones: birthdays and babies, Easter, Thanksgiving and Christmas.

In an interview at the offices of his attorney, Patrick M. Regan, in Northwest Washington on Monday, Marcus Glover was poised, thoughtful and pensive.

“Throughout the year, we’ve had these moments of joy — and I think ‘Mom would have loved this,’ ” said Glover, 31. Pausing a moment to reflect on his life now, he added: “I see so much of her in my life story.”

He spoke with pride, detailing how DKW Communications, the company his mother had been working for, invited the family to its holiday party, where it was announced that the company’s employee of the year award was being renamed in honor of his mother. Carol Glover won the award in 2014.

And then come the pangs.

Even as he and his older brother Anthony cuddle their daughters, both born last year, their thoughts are never far from what happened on Jan. 12, 2015, when an ordinary commute became anything but. (Marcus’s newborn daughter’s middle name is Caroline, a tribute to his mother.)

Tuesday, however, will pass quietly.

For Marcus, that means going to work and finalizing plans for celebrating his oldest daughter’s second birthday. For Anthony, his wife and two children, that means firming up plans for a move that will take them to Europe this year.

Marcus no longer rides Metro. He can’t bring himself to board a train.

“It’s too difficult mentally, emotionally,” he said.

When he feels out of sorts, he pulls up one of the many text messages and emails from a mother who was always the family’s “chief encourager.”

The family has moved ahead — and in ways he thinks that alone would make his mother proud.

“We are constantly reminded that we are her legacy,” he said. “I know my mother would appreciate that we have continued to live our lives.”