The MBTA's yearlong pilot program of late-night weekend service begins Friday.
The T's subway and 15 major bus routes will run until around 3 a.m. The service will operate at the same stations and stops it does on weekdays, and fares will be the same.
The last Red, Orange, Blue and Green line trains will depart downtown stations at about 2:30 a.m. on Friday and Saturday nights.
The extended late-night service will operate approximately every 15-20 minutes, with more frequent service in the system's core.
The program will cost about $17 million for the year, mostly in the form of salaries for MBTA employees. State funding and corporate sponsors are helping to foot the bill.
The T does not plan to break even on the yearlong pilot program.
This is the second attempt by the MBTA to extend service past 1 a.m. An all-bus iteration was discontinued in 2005.
But Transportation Secretary Richard Davey says he's confident this new program will work.
"I think bus service alone didn't work," he told WBUR. "And this is going to be both. And also today you can check your devices, iPhones, etc., to see how long you have to wait, and I think that was a challenge [back then] as well."
With reporting by the WBUR Newsroom and The Associated Press