As the TTC's CEO, Andy Byford sometimes rides the bus at 4 a.m., just to see what the service is like.

He takes the same Blue Night buses to dark-and-early interviews with CBC's Metro Morning, is fond of spending New Year's Eve working at various subway stations, and when he's flying somewhere, he uses the 192 Airport Rocket to get to Pearson.

In the words of one local transit expert: "Who does that?"

Byford announced this week that he'll leave his post in December and head to New York City to tackle, in his words, "arguably the toughest job in transit." But he's also leaving a big one behind in Toronto, and there are worries the TTC will slip in his absence.

"My big concern is that Andy was an articulate spokesman for the projects that he got behind," transit advocate Steve Munro told CBC Toronto in a phone interview.

"I am not entirely sure without him being there to argue for them they're going to have the same momentum."

Mayor John Tory handed these flyers out to TTC subway commuters last winter, but transit advocates say the downtown relief line needs to stay on the front burner. (John Rieti/CBC)

And these are big projects, Munro says, including the ridership growth strategy (now punted to early-2018, even though ridership is stagnating right now) and the downtown relief line (still in the early planning phase with 2031 as the projected opening date).

"The relief line really needs a push, and it needs a push to keep it moving," he said.

Moments later Munro has to take another reporter's call, this time from the New York Times.

The Daily News has already put Byford on the front page, with the headline: "Can he save the subway? MTA imports fix-it big from Canada."

TTC in good hands, Byford and agency chair say

Byford was unavailable for comment for this story, but is set to do a series of exit interviews with the media in the coming weeks.

In his farewell remarks, Byford said a five-year plan for the TTC is in place and the executive team he's leaving behind — of which women now make up 50 per cent, something he's extremely proud of — are well-prepared to handle that work, even though it can be a "thankless, relentless task."

"They can hit the ground running in 2018," he said.

The TTC's next leader will face plenty of tough questions when it comes to the Scarborough subway extension, which is intended to replacing the aging RT system pictured here. (John Rieti/CBC)

Rick Leary, Byford's deputy, will take over the top job at the TTC on an interim basis.

TTC Chair Josh Colle says an executive search for a new CEO is already underway, and he's hoping a new leader will be in place by next summer, ahead of the municipal election.

Whoever takes over the post will likely have the task of providing advice to city council in 2019 about how to proceed with the Scarborough subway extension, once the TTC has 30 per cent of the design work done and a better handle on how much it will cost. The current estimate is $3.35 billion.

Colle says he expects the CEO to provide their "best, unvarnished opinion, just like Andy always has," however the final decision will be council's.

He expects the next leader to respect that choice, "even if they're decisions that some members of the public don't like."

While losing Byford isn't ideal, Colle says things are still looking up for the TTC. All three levels of government are aligned in their desire to build transit, he says, while projects are actually getting built.

"I'm actually excited going forward, and I think transit riders should be," said Colle.

Focus on customer service, expert says

The TTC's King Street pilot project is prioritizing streetcar service in the downtown core, but without Byford it will lost one of its most vocal proponents. (John Rieti/CBC)

Murtaza Haider, an associate professor at Ryerson University's Ted Rogers School of Management who focuses on transit issues, doesn't expect the next leader to change the city's transit priorities.

"I don't think Byford was able to influence the development agenda," he said.

Instead, Haider says the TTC should try to maintain the culture Byford installed of putting customer satisfaction first.

Haider points to the increased rush-hour train service on the subway as a good example. During Byford's tenure, the TTC rolled out automatic train control, but it also made other small improvements like tweaking how pedestrians flow onto the platform.

"These are the changes that were needed to manage the constrained off-track infrastructure better," Haider said.

Haider says the outgoing CEO's efforts to clean up trains and tracks — it's not an overstatement to say the TTC was frequently putting out small subway fires when Byford arrived — have also been successful.

"These are small steps that make big changes," he said.

Byford's biggest win will likely be getting the Toronto-York Spadina Subway Extension project back on track. But Haider says he'll be best remembered for his compassion and willingness to be held to account.

Byford hasn't been shy about apologizing after subway breakdowns led to "horrendous" commutes. When it comes to Bombardier's repeatedly-delayed delivery of new streetcars, he told reporters "they know I'm not a happy bunny." And before the King Street pilot project, he called streetcar service on the TTC's busiest surface route "embarassing."

All of that, Haider says, "was refreshing to see."