The head of the MBTA’s oversight board says the hoped-for transformation of the transit agency  has a long way to go yet.

“We’re still at the very beginning,” says Joseph Aiello, the chair of the MBTA’s Fiscal and Management Control Board. He says the collapse of the T during the winter of 2015 exposed the sorry state of the agency. “We were probably in as dark a hole as you can possibly be in,” he says.

But Aiello is not all gloom and doom. He says the agency is moving ahead with an overhaul of the Red and Orange lines that will double their capacity and committing to an annual maintenance schedule that will prevent the sort of deterioration of service that occurred the last time the two lines were upgraded. “We’ve got a pretty radical transformation going on,” he says.

The T is also considering a plan to double the capacity of the Green Line and exploring a reimagining of commuter rail, not to mention a host of other initiatives. Aiello is cautious about the need for more revenue. He says the agency has enough money for the next five years and adds that broad-based taxes are off the table.

But he acknowledges a revenue discussion might take place after the agency develops a clearer picture of its financial future beyond the next five years. He says the long-used estimate ($7.3 billion) of what the agency needs to bring its assets into a state of good repair is too low and cost estimates for the Green Line overhaul are still being developed. “We’ll probably understand where we are in terms of a long-term, 20-year spend by mid-year or late in the year,” Aiello says.

Aiello says he would like to see some signal from the Legislature on whether they will fund the overhaul of the Green Line.

To criticism that the T should just hire more people and speed up the agency’s transformation, Aiello says it’s not that simple. He says most of the needed improvements are disruptive to a system that needs to run even while it is being overhauled, so most work has to be done late at night or on weekends. He says the T doubled its construction productivity during overnight periods and is trying to triple it, but there is only so much time.

“We’d rather go slow and get it right rather than go fast and, as we say in East Boston, screw it up,” he says.

Aiello appeared with Carolyn Ryan of the Greater Boston Chamber of Commerce and Chris Dempsey of Transportation for Massachusetts at a CommonWealth Newsmakers event on November 27 that was condensed into this week’s Codcast.

Here are a few other highlights from the discussion:

— Aiello says he never met Gov. Charlie Baker before being appointed chair of the control board, but he is now a big fan. He credits Baker with saving the Green Line extension.

— He says funding for South Coast Rail is all set, but administration officials say they are still working on finding the money.

— Responding to a question from Ryan, Aiello said the T needs to rethink its pricing for commuter rail and possibly other services as well. But he says that debate — deciding whether to charge based on length of trip, time of day, or ability to pay — is likely to be divisive.

— “Driving is way too cheap,” says Dempsey, who called for putting a price on driving that would encourage people to get out of their cars or shift to off-peak times. He said putting a price on driving could also help fund some of the transit improvements Aiello mentioned.