Trains are still running sluggish this week as the MBTA works to restore normal service on the Red Line following last week’s derailment. A chorus of voices, including that of Mayor Martin Walsh, is pushing the T to halt a system-wide fare raise planned for July 1, citing poor standards of service and numerous derailments in the past month. Regional transportation leadership was quick to firmly rebuff the request.

A southbound Braintree train derailed last Tuesday before the morning commute, coming off the tracks at about 6:10 a.m. just outside JFK/UMass station and sliding more than 1,800 feet, damaging the rails, the train car itself, and three signal bungalows that control switches at the station. One bungalow was “almost entirely wiped out” said MBTA General Manger Steve Poftak.

Third rail and power repairs at the station are complete and Braintree trains can now run through the station at reduced speeds. The arrival clocks are tied to signal operations, so they remain out of commission for now.

“We have signal crews not only trying to figure out what we can salvage, but also if there are alternatives that can do this faster,” Poftak said during a T board meeting on Monday. “We don’t have a level of certainty on that that would give us the ability to give a concrete timetable.”

Poftak said the switching equipment had been slated to be replaced as part of a $113-million overhaul of Red Line signaling equipment - but not quite as quickly as the T now has to work to restore the equipment, he said. Until it can be restored or replaced, the Red Line through JFK/UMass will be controlled by manual signals, and the effects of the damage can add 20 to 30 minutes to a commute, Poftak said at the MBTA’s Fiscal and Management Control Board meeting.

T officials have bolstered local service by allowing Commuter Rail trains to take passengers with Charlie Tickets or Charlie Cards along the Red Line route, which continued through Tuesday.

Inspectors ruled out foul play and operator error as possible causes of the derailment, but they have yet to figure out whether something went wrong on the car that went off the rails or on the tracks or switch.

The investigation is zooming in on parts of the 50-year-old train car that went off the rails as possible causes of the derailment, Poftak said. The train involved in the incident first entered service in 1969 and underwent renovations in the late 1980s, while its truck assembly dates back to 2014.

Officials said two separate outside reviews are planned for the MBTA; they will look at derailments and broader safety questions. The derailment last week was the fifth on an MBTA passenger train this calendar year, not the fourth as officials had previously said, and the 24th since the start of 2015.

LTK Engineering is contracted to conduct a review of all MBTA derailments since the start of 2017, Poftak said. The firm’s report would be ready for public release within three months, he said.

The other review called for by advocates and announced by T officials on Monday will examine safety across the MBTA system. Board members will draft a plan for the review in the coming days and offer additional information at next week’s meeting.

The derailment comes just a few weeks before the announced fare hikes will increase the cost of using the MBTA by an average of 5.8 percent. For local officials, like City Councillor Michelle Wu, who has been pushing for a free T for some time now, the derailment meltdown was a bridge too far. Mayor Walsh, who in 2017 complained that press coverage makes a mostly “reliable” MBTA “sound like it’s crumbling,” added his voice to the irritated chorus on Twitter. “There should be no fare increase until the Red Line is fixed,” he wrote. “The MBTA must act with urgency and it’s unfair to ask riders to pay more until the Red Line is fully operational.”

After an event on Tuesday, the mayor told reporters that he supported the fare hikes when the thinking was that they would result in better service. “I’ve been pretty sympathetic all along, and I’ve been criticized for that -- being sympathetic -- but right now, it’s time for action,” Walsh said. He asked that T leadership “get their act together” and said there is no reason they cannot delay the planned far hike.

A Change.org petition demanding a halt to the fare increase had more than 6,200 signatures as of Tuesday afternoon.

Transit officials hardly sounded open to the idea at the board meeting on Monday. “I think the requests to delay the fare increases are just an expression of frustration in the wake of the derailment,” Transportation Secretary Stephanie Pollack told reporters after the meeting, according to the State House News Service. “I am totally sympathetic to that level of frustration. I just think the fare increase is the wrong target for that frustration.”

For his part, Governor Baker said that despite the pace of improvements “we’re headed in the right direction” in updating the aging MBTA system. He and transit officials point to new Orange Line and Red Line cars being tested over the next two years and fully swapped in by 2022 and 2023, respectively. Related to the new cars, a $218 million signal system upgrade is slated to be completed by 2022 on the Orange and Red lines.

“For our governor not to understand that it requires deeper financial investment, so that these changes can go into effect faster, is a little bit baffling,” Boston City Council President Andrea Campbell said this week.

State Sen. Nick Collins, whose district overlays the parts of Boston most impacted by the Red Line derailment, emphasized again his objection to fare increases without systemic improvements. “I have been opposed to fare hikes from the beginning and will remain so until there are plans for significant, game-changing investments that will earn back the public’s trust,” he said. “I applaud the mayor for his stance and think Boston deserves a seat on the board.”

The Fiscal and Management Control Board, which voted 4-0 to approve the fare hike, has no local seat for Boston. It was established after the winter of 2015 slammed the region and its transit network. It will likely be reconvened in 2020, and Walsh tweeted that he thinks Boston’s disproportionate vulnerability in the case of a downed MBTA merits a seat on the board.