Ninety of the Green Line’s 204 trains were built in 1986, portions of the signal system date to the early 1900s, and power cables — one of which failed Saturday, causing delays on the Green, Red, and Orange Lines — are prone to breakdowns.

Fewer than 70 percent of Green Line trains arrived on time during a recent six-week period, according to the report, which blamed the spotty service, in part, on aging equipment.

MBTA officials reviewed a report Monday that confirms what veteran Green Line riders already know: The system is plagued by crowded trolleys and frequent delays.

Jeffrey D. Gonneville, the chief operating officer of the MBTA and author of the report, said the agency hopes to improve service by using GPS devices recently installed on Green Line trolleys to monitor slowdowns and improve the timing of stoplights on part of the Green Line.


The T also plans to consolidate four stops on the B Branch — BU West and St. Paul, Babcock, and Pleasant streets — into two stops, to allow trolleys to move more quickly along Commonwealth Avenue.

But Rafael Mares, a lawyer at the Conservation Law Foundation, pointed out that although the MBTA capital plan includes money for new trolleys on the proposed Green Line extension, it doesn’t set aside any funding to replace the creaky, Reagan-era trolleys on the rest of the Green Line.

“Ultimately, there isn’t going to be a solution to all the problems until we have sufficient revenue” to buy new trains and upgrade rusting equipment, Mares said.

Stephanie Pollack, the state transportation secretary, said the T is completing an inventory of all its trains and buses before deciding how much money to spend on new vehicles.

“We need to understand all the needs of all the different vehicle fleets, and then we can prioritize which ones we want to do, and also how we want to do that,” she said.


Green Lines trains could be leased, instead of purchased, and the state could try to find private funding for trains, she said.

“The only model is not just buying vehicles and running them the way we always have,” Pollack said.

The report, which was delivered at Monday’s meeting of the Fiscal and Management Control Board, did not touch on the Green Line extension. T officials are expected to decide next week whether to scale back or even scrap that long-awaited project.

On Monday, T officials did grapple with a possible replacement for the late-night service that was canceled in March.

Officials considered an idea proposed by Transit Matters, an advocacy group, that recommended running buses every hour, seven nights a week, along eight existing routes.

T officials said the service would be relatively easy to launch, but would cost three to four times the $1.4 million price tag suggested by Transit Matters.

That raised alarms among some board members, who decided not to take any action on the plan.

”The initial sense is it’s probably pricier than the proponents of it had originally proposed,” Pollack said. But the T will continue to study late-night service options and “see where it takes us,” she said.

Michael Levenson can be reached at michael.levenson@globe.com. Follow him on Twitter @mlevenson.