Here’s what we know about the Green Line crash — and the pending investigation

The National Transportation Safety Board is working to figure out what happened Friday evening when two MBTA Green Line trains crashed into one another near Boston University, leaving 25 people injured.

Investigators from the NTSB were on the scene Sunday gathering information such as how fast the train was moving when it rammed into the backside of the trolley ahead of it, Jennifer Gabris, an agency spokesperson, told The Boston Globe.

“At this early stage of an investigation, NTSB does not state a cause but will provide factual information when available,” she said in an email. “Investigations involving injuries and other major investigations currently take between 12 and 24 months to complete.”

Update: In an update on their investigation Monday, the NTSB said 27 people, not 25, were taken to hospitals with nonlife-threatening injuries. The agency also said: “Preliminary review of the event recorder data indicated that the train that was hit was traveling at approximately 10 mph. The striking train overtook the other train at approximately 30 mph.” The agency noted this preliminary information may change as the investigation continues. “NTSB will issue a preliminary report within 30 days of completing on scene work,” the update said. Read the full update here.

MBTA officials on Saturday placed one of four trolley operators on board the two trains on paid administrative leave — a decision that was made based on developments in the ongoing probe, a spokesperson for that agency told the newspaper.

Passengers on board and eye witnesses of the collision described a jarring scene.

“There were big crowds of people rushing to get out of the train. One girl had blood all over her face,” Miltch Pierre, 21, who was working inside nearby Blaze Pizza on Commonwealth Avenue at the time, told the newspaper. “I saw two or three get taken away on ambulances, people in neck braces. It was wild.”

Here’s what we know about the crash — and the investigation — so far:

What happened, according to the MBTA

Two Green Line B branch trains were heading west on Comm. Ave. on Friday evening when the trailing train collided with the train ahead of it just after 6 p.m., MBTA General Manager Steve Poftak told reporters at the scene.

According to Poftak, Boston EMS said all of the 25 people injured were conscious and alert, and their injuries were nonlife-threatening.

“Obviously our first thoughts are with our passengers and our employees who were injured,” Poftak said.

According to Poftak, MBTA infrastructure appeared damaged as a result of the crash, and some of the trains’ axles were de-railed.

The MBTA’s safety department was conducting an investigation at the crash site on Friday, as were the agency’s state and federal partners, Poftak said.

He did not offer any details regarding what may have gone wrong and informed reporters at several times during the press conference that he would not speculate on what exactly happened.

“We will obviously get to the bottom of this,” Poftak said. “This should not happen, and we will find out why it happened, and we’ll ensure that it won’t happen again.”

Asked if there were any safety devices on board the trains that would have prevented a crash like this one from happening, Poftak said there is not a specific mechanism.

“Obviously we have drivers and we have several layers of braking systems that could be used,” he said. “Part of our analysis will be what speed was the trailing vehicle driving at and then were any of these systems activated.”

On Saturday, the MBTA placed one of the four operators on board the trains at the time of the collision on leave based on information uncovered in the investigation, MBTA spokesman Joe Pesaturo told the Globe.

The four operators were among those injured in the crash.

Pesaturo declined to name the driver who was placed on leave. According to the newspaper, the operator has worked for the MBTA for seven years and was piloting the first car of the two-car train that struck the other trolley from behind.

Regular service on the line resumed Saturday morning.

What passengers and witnesses said

Flavio Correa, a 45-year-old Allston resident, was on one of the trains with his wife, according to the Globe.

Neither were badly injured. Correa bumped his elbow and knee, and his wife hit her chest.

“It was so fast,” Correa said. “Very, very fast.”

Some passengers suffered cuts on their legs and arms, Correa told the newspaper. He saw one girl with a small cut on her chin.

According to the Globe, many of the injured passengers were brought to Massachusetts General Hospital and St. Elizabeth’s Medical Center.

A spokeswoman for MGH said Saturday that five people were treated and released. The newspaper did not hear back from representatives for St. Elizabeth’s and Steward Health Care.

Pierre, the Blaze Pizza employee, said he felt the restaurant shake — something he never felt before.

“I was like, what could possibly be shaking everything this hard?” Pierre said. “When I turned around, there was a bunch of smoke outside.”

Boni Lacourse, 23, and Matt Heerema, 24, two recent Boston University graduates, were on board an inbound train that traveled next to the two trolleys not long after the crash, they told the Globe.

“I saw the aftermath,” Lacourse said. “I saw one of the train drivers come out of the train — she was very disturbed, as you could imagine. She came out and was wanting to make sure everybody was OK and everybody was able to get off the train.”

Their Friday evening trip on the T was the first time both Lacourse and Heerema were on the train since the COVID-19 pandemic began last year, they said.

“We were going downtown, and to see this, it doesn’t make you feel great,” Lacourse said. “It’s a rare occurrence, but it doesn’t make you feel great.”

Where the NTSB investigation stands

Four NTSB investigators, with specialties in “operations, crashworthiness, and human performance,” were at the crash site on Sunday, Gabris, the spokesperson, told the Globe.

Gabris said “parties to the investigation” have been identified. She did not release any details about the operator who was placed on leave.

“NTSB does not release the names of those involved in the accidents we investigate,” Gabris said.

While NTSB investigations involving injuries typically take between 12 and 24 months to wrap up, the agency is expected to release a preliminary report on the crash in the coming weeks, Gabris said.

The Suffolk County District Attorney’s Office has also indicated it is investigating the incident.

Gov. Charlie Baker said he’s ‘anxious to find out what happened’

Gov. Charlie Baker, at a housing event in Everett on Monday, told reporters he spoke with Transportation Secretary Jamey Tesler several times about the crash during the weekend, The State House News Service reports.

“I’m really anxious to find out exactly what happened because this could have been a far more significant incident than it was given the estimates that are out there about how fast that train was traveling when it hit the other train,” Baker said.

Baker anticipates the NTSB’s investigation to be “the final word on this,” he said. Once the agency publishes its findings, the Baker administration will “work to move on the things that they recommend,” he said.

According to the Globe, the NTSB has investigated two other crashes on the Green Line, including a 2008 collision in Newton in which a train operator was killed after she went through a stop signal and hit a train stopped ahead of her.

The NTSB found that Ter’rese Edmonds, 24, suffered from fatigue and could have fallen asleep briefly while at the controls, the newspaper reports.

The agency criticized the MBTA that year — and again the following year when Green Line operator Aiden Quinn crashed his train near Government Center while he was texting — for not putting in place technology that stops a train if it moves too quickly toward an obstacle.

The technology has so far been installed on the MBTA’s other rail lines, according to the Globe.

Pesaturo told the newspaper the Green Line is set to receive the $170 million upgrades next year.