Photo courtesy of State House News Service.

Five days after a train derailed while approaching JFK-UMass station on the Red Line, the MBTA on Sunday said it has resumed seamless service to Quincy and Braintree stops but asked customers to build an extra 20 minutes into their planned travel times as they begin another work week.

Riders no longer need to transfer to another train at the JFK-UMass station, officials said, but while service has resumed on all tracks through the JFK-UMass station trains continue to operate at restricted speeds. In the wake of the 6:10 a.m. derailment Tuesday, the authority has made “around-the-clock repairs to signals and track infrastructure” using hundreds of employees and the service announcement was made Sunday after a series of successful tests.

“We are pleased to be able to resume direct service to the Braintree branch, but we still have a lot of work to do,” MBTA General Manager Steve Poftak said in a statement. “Recovery operations are continuing with a goal of full service, but riders should allow additional time for their commutes because track switches must be operated manually until repairs are completed. For Monday’s commute, we will continue to offer additional commuter rail trips and will continue to keep riders routinely updated on the schedule.”

Some countdown clocks that let passengers know when to expect trains remain inoperable due to ongoing signal work, but most Red Line stations have had their clocks restored, according to the T’s Twitter account.

The MBTA this week hired LTK Engineering to conduct an outside review of all derailments in the past two years, and on Friday, Poftak hinted that officials “may expand the scope” of what the firm is asked to do.

Asked if he wanted to see additional funding allocated to the MBTA, Poftak did not answer directly, pointing to a “fully funded” capital plan. The MBTA will introduce new cars on the Orange Line this summer and the Red Line next year and will eventually replace both fleets entirely, and Poftak said a $113 million program is already underway to replace all Red Line signals – although those damaged in Tuesday’s derailment were set to be the last ones updated.

Baker has also highlighted preexisting investments in the T this week in response to the derailment. He touted plans to spend $8 billion over the next five years on various MBTA infrastructure improvements when speaking with reporters Thursday.

“I think everybody would like the T to be fixed tomorrow, and we certainly put the resources on the table, the largest four-year investment in the history of the T to invest in its infrastructure,” Baker said. “But we can’t shut the T down to do the work every day, all day, because there are literally hundreds of thousands of people who rely on it every day to get where they go, so the work has to be done at night and on weekends, and that means it’s going to take longer.”