MBTA OFFICIALS ANNOUNCED on Monday that the rollout of new Orange Line vehicles is being delayed again, this time until sometime this summer.

T officials say 10 Orange Line vehicles have already been delivered from the Chinese manufacturer and two more are due to arrive this week. Full rollout of all 152 vehicles is scheduled to be completed by December 2021. The arriving vehicles were expected to start entering service this month, but T officials now say they won’t be ready to go until sometime this summer.

Jeffrey Gonneville, the T’s deputy general manager, said there is no problem with the vehicles themselves. The holdup is software being developed for the vehicle’s signal system by the French contractor Alstom.  Gonneville said the software will allow the transit system to automatically detect any vital equipment failure requiring a shutdown of train service.

Gonneville said the T expects to introduce two new six-car train sets into service once the software is fully developed and tested. As he said when he announced the initial delay in January, Gonneville said the software issue is the last critical item to get resolved.

Bus system overhaul has lots of moving parts

Members of the T’s Fiscal and Management Control Board on Monday began trying to wrap their heads around all of the moving parts involved in revamping the bus system.

The T’s so-called Better Bus team said it has finished gathering extensive public feedback on 47 proposed route changes and concluded that 20 are likely to move forward. The rest are split between routes that require more review and 10 that are unlikely to happen this fiscal year.

One route put on the back burner, the No. 93 bus running from Charlestown to Haymarket, came under fire on Monday from Charlestown residents commuting to jobs in Boston’s Chinatown. The residents, speaking through Chinese interpreters, said the bus often runs late, changes routes unexpectedly in bad weather, and occasionally refuses to stop for Chinese riders. The riders also urged the T to extend the 93’s route to have it terminate closer to Chinatown.

“We take any reports of discrimination very seriously,” said T General Manager Steve Poftak.

While the T explores changes in its existing bus route structure, the transit authority is also considering a total redesign of service to better serve the needs of the region and boost ridership.

Adding another layer of complexity, the T is also trying to figure out a way to upgrade its 10 bus repair facilities, whose average age is 54 years and in nearly every case are servicing far more buses than they were designed to handle.

The Albany and Quincy garages are the first priority, since they can only accommodate the T’s older buses, which are scheduled to be replaced by 2022.

Eric Stuthoff, the T’s chief engineer, said it will take 13 years to bring all of the bus facilities up to a state of good repair, capable of handling 1,000 buses. But members of the control board said the bus system cannot wait that long since the number of buses needs to expand significantly to improve service. The bus fleet also needs to change, shifting from diesel and hybrid vehicles, to battery-operated equipment.

No discussion about new revenues scheduled yet

The MBTA control board discussed taking a message about new revenues to the Legislature three weeks ago, but no further action has been taken yet and none is scheduled