On the evening of February 3, 2015, a commuter train on Metro-North Railroad's Harlem Line struck a passenger car at a grade crossing on Commerce Street near Valhalla, New York, United States.

The board's 2017 final report determined the driver of the SUV to be the cause of the accident, after finding no defects with the vehicle or crossing equipment, or issues with the train engineer's performance.

[42] All the deaths save one of the passengers were attributed to blunt force trauma; that exception was due to burns and other injuries making it difficult to determine the cause.

[25] A police helicopter with thermal imaging equipment scanned the nearby Kensico Cemetery in search of survivors who might have wandered away from the scene and collapsed into the snow, but found none.

[52] Following the accident, some commentators discussed its relation to suburban life in central Westchester County, where many communities originally developed due to commuter rail.

[53][54] Early fears that the fatalities would mostly be from Chappaqua were unfounded, as most commuters from the hamlet ride in the rear cars for the shorter walk to the parking lot once the train does stop.

"[53] Writing in The New Yorker, Sam Tanenhaus, who by then had been living in nearby Tarrytown for over 25 years, saw the accident as highlighting how:[54] ... the paradox of Westchester—its lure and deception—is captured in its antiquated, overcrowded tangle of bucolic "parkways".

In addition, all the five passengers who had died were men, recalling the mid-20th century when commuters were overwhelmingly male, working in the city while their wives tended the suburban homes.

Tanenhaus likened the accident to something from the works of writer John Cheever, who lived in nearby Briarcliff Manor and set much of his fiction amid the suburbs, featuring commuters as his characters: "[He] might have conjured the haunting details of the Harlem Line crash: the lead-footed irony of 'Valhalla,' the survivors wandering through the cemetery to safety.

"We do have grade-crossing accidents, and most of the time it's fatal for occupants of the vehicles, and not for train passengers," Robert Sumwalt of the NTSB told The Journal News, Westchester County's main daily newspaper.

But Steve Ditmeyer, a former Federal Railroad Administration (FRA) official, told the Associated Press it would be impossible to be sure that an under-running shoe lifted the rail without also doing tests to see if the same thing would happen in the more common over-running configuration.

[32] The NTSB team theorized that the fire aboard the train might have been caused by gasoline from the SUV, ignited by a spark from the third rail, which had pierced the car's fuel tank.

[54] Lance Sexton, a Manhattan resident who commutes to the area to assemble electronic equipment, described using it to The New York Times: "[C]oming down the hill of the cemetery, you have to put the brakes on earlier ...

[61][f] The crossing had undergone upgrades in recent years, including brighter lights and an additional sign warning passing drivers not to stop on the tracks.

[32] Three days later, the NTSB investigators announced that all safety features at the crossing—the gate, its flashing lights, the train's horn, and a sign 65 feet (20 m) away warning drivers not to stop on the tracks—were in good working order and had functioned properly at the time of the accident.

In addition, the driver stopping within the crossing and leaving the vehicle during the warning period, the third rail penetrating the passenger car, and the post-accident fire were all found to be contributing factors.

[65] The original question, why Ellen Brody had driven forward into the path of the train and thus made the accident inevitable, could not be answered conclusively due to her death.

The NTSB noted that the Federal Railroad Administration had been working to update its grade crossing database and provide it to the manufacturers of GPS systems; it expected to have that done by late 2017.

"Someone in a good state of mind, as this driver apparently was, who is aware that they are in close proximity to a railroad crossing, and in imminent danger of being struck by a train going 60 mph [97 km/h], would not act this way", Sumwalt said.

He noted that in another grade crossing accident in California shortly after the Valhalla crash, a driver had turned his pickup truck onto the tracks inadvertently out of confusion created by a nearby intersection.

"[77] Since the accident, the town of Mount Pleasant and the Metropolitan Transportation Authority (MTA), Metro-North's parent agency, have responded to some of the issues discussed in the NTSB report.

One woman from Thornwood, a hamlet of Mount Pleasant just north of the accident site, drew applause at a later meeting when she said she had learned how to handle grade crossings during her high school driver's education classes.

It added to its website a page developed in conjunction with Operation Lifesaver (OLI), an organization that works to promote rail safety among the public, particularly at grade crossings.

Informational posters, reminding passengers to "Wait Behind the Gate" when they drive through grade crossings, went up in trains and at stations on the Metro-North, the Long Island Rail Road (LIRR), and the New York City Subway.

Officers handed out pamphlets to drivers, pedestrians and train passengers at the many grade crossings in the metropolitan area, but also went as far as issuing summonses to violators, even arresting five, by November 2016.

"[83][78] Six years later, Senator Chuck Schumer secured a $100 million federal grant for Metro-North to improve safety at grade crossings; most of it would be spent to build an overpass over the tracks and the Saw Mill River Parkway at Roaring Brook Road, near a school in Chappaqua further up the line.

Alan Brody complained that most of the railroad's efforts have gone to implementing positive train control as the NTSB had recommended after the Spuyten Duyvil wreck, which would not have prevented the Valhalla accident any more than the CCTV would.

[88] In 2018 it was disclosed that Smalls had reached a confidential settlement of a legal claim he had made against the MTA; his attorney said the engineer had never returned to work, was no longer employed by Metro-North, and had post-traumatic stress disorder as a result of the crash.

[89] Around the crash's fourth anniversary, The Journal News reported that lawyers for injured passengers and families of the dead were focusing on the third rail's failure to break up as a contributing cause.

[24] In 2024, a jury hearing a suit brought by 30 passengers found the railroad mostly liable for the accident, through its failure to maintain the third rail and properly train Smalls.