“MBTA trains are designed and equipped with safety features to prevent them from moving when the passenger doors are obstructed,” said a preliminary report on Lalin’s death posted on the National Transportation Safety Board’s website. “NTSB investigators examined and tested the railcar involved after the accident, identifying a fault in a local door control system that enabled the train to move with the door obstructed.”

The NTSB said the T “immediately initiated a fleet inspection looking for the identified fault in other railcars to prevent reoccurrence. The MBTA reported that no other similar faults were found during the inspection.”

Lalin, the report said, was trying to exit the train at the time and was ultimately dragged “105 feet and onto the surface below, near the tracks.”

The report said surveillance video reviewed by the safety board showed Lalin attempted to disembark from the six-car train around 12:30 a.m., as the doors were closing. The footage showed Lalin’s right arm became trapped in the door during his “attempt to exit,” the report said.

Lalin’s nephew, Kelvin Lalin, 30, of Everett, said Monday in a phone interview that the report was “heartbreaking” and “sickening” for his family to read.

“The MBTA killed my uncle,” Lalin said, asserting that his uncle’s death was the result of “direct negligence” by the agency.

“I don’t know what’s going on with the MBTA, where the money’s going,” he said. “We have these so-called new trains,” but older trains remain in use. “It’s a slap in the face for me. ... All the family has is a cremated family member who was basically cut into pieces.”

The Globe has reported that the the MBTA is still waiting for delivery of hundreds of new Red Line train cars from a Chinese company first contracted in 2014. Those are supposed to replace the old cars like the one involved in the incident.

In a separate statement Monday, the MBTA said it would “once again like to extend its deepest condolences to the Lalin family regarding this heartbreaking incident.”

The T added that “immediately following” Robinson Lalin’s death, “the door systems throughout out the Red Line fleet were tested for this specific problem, and MBTA personnel found all components performed as designed and did not identify any additional instances of the circuitry problem the incident car experienced.”

The agency said previously that the train involved in Lalin’s death entered service in 1969 or 1970.

The statement said T personnel who perform regularly scheduled preventative maintenance on the fleet are supplementing existing door inspection protocols with additional testing to prevent a repeat of the April tragedy.

“The MBTA stresses that investigations by the NTSB, Transit Police and the MBTA Safety Department are ongoing, and if further steps are warranted to enhance safety, then the MBTA will certainly take such immediate and appropriate action,” the statement said. “The safety and well-being of every MBTA rider is of the utmost importance.”

The T also said it’s been working “aggressively” to improve safety as part of an “unprecedented” $8 billion investment in infrastructure and vehicles over the past five years.

In addition, the T said, the agency has nearly doubled the size of its Safety Department in recent years, training “thousands of employees to help foster a culture in which safety” is prioritized.

That was small comfort to Kelvin Lalin, who told the Globe Monday that the T hadn’t offered an apology to his family, who laid his uncle to rest over the weekend. Robinson Lalin was originally from Honduras and had two children, Kelvin Lalin previously told the Globe.

“We are really in pain and grieving my uncle,” Kelvin Lalin said.

An MBTA spokesman said Monday Transit Police officers notifying Lalin’s family of his death had “extended condolences, on behalf of the MBTA, for the loss of their loved one,” and that T General Manager Steve Poftak had publicly expressed his condolences to the family.

The NTSB said Monday that its team investigated the train equipment at the scene of the tragedy and also reviewed security footage and observed train operations. The agency said the investigation’s next phase will focus on the T’s passenger train equipment and operating procedures.

A safety board spokesman said the agency wouldn’t be commenting beyond the preliminary report on Monday. The agency will release a final report at a later date.

A spokesman for Suffolk District Attorney Kevin R. Hayden’s office, which is also investigating the crash, declined to comment on the NTSB report Monday.

Stacy Thompson, executive director of the Cambridge-based LivableStreets Alliance, a transit advocacy group, said the report illustrates the perils of underfunding the T.

“I think there is a lot to learn from this moment,” Thompson said via e-mail. “It illustrates the real, and in this case, incredibly tragic consequences of chronically under investing in the T.”

Josh Ostroff, interim director of Transportation for Massachusetts, another advocacy group, said in a separate statement that safety on the T must be the highest priority.

“The tragic loss of Robinson Lalin’s life from the Red Line door malfunction followed many other events that led to fatalities and injuries,” Ostroff said. “We support the MBTA’s efforts to instill a safety culture, but we are also seeing the results of decades of underinvestment where we are relying on vehicles and systems that should have been replaced decades ago.”

Ostroff said the “current level of capital investment may be unprecedented, but the deficiencies the state is seeking to correct are well known. Safe and reliable public transit is critical for Massachusetts, and we urge state leaders to commit to the policies and investments necessary to achieve this goal.”

Correspondent Nick Stoico contributed to this report.