Serious questions are being asked about whether the safety devices at a North Carolina railroad crossing were working when a young mother and her 5-year-old son were killed by an Amtrak train just four days before Christmas.

The crash – on tracks leased and maintained by Norfolk Southern – remains under investigation, but neighbors said the cross arms that were supposed to protect the mother and other drivers had been malfunctioning.

“They’ve been going just wacko, up and down and up and down, and there’s no train coming,” James Shanke Jr., a neighbor who witnessed the crash, told The Herald-Sun of Durham, N.C.

The car was hit at 10:30 a.m. Dec. 22 by an Amtrak train loaded with more than 200 passengers on its way from Charlotte, N.C. to New York City. The crash happened in Efland, an Orange County community about 20 miles northwest of Durham.

Gail Emory, a woman who works near the crossing, told the Chapel Hill News that the warning devices malfunction so frequently that she keeps the phone number for Norfolk Southern on a Post-It note on her desk.

However, the railroad and state officials have accused the driver, Erin Lindsay-Calkins, 26, of Efland, of colliding with the safety gates with her car and driving into the train’s path. Calkins and her 5-year-old son died. Her 3-month old daughter survived and is in fair condition at UNC Hospitals.

“There is not a history of any malfunctions at that crossing,” a Norfolk Southern spokeswoman, Susan Terpay, told the Chapel Hill newspaper.

Emory and others said they’ve called the railroad dozens of times over the past three years reporting erratic behavior by the warning arm and flashing lights.

Emory told the newspaper she often sees the crossing arm down when it should be up and up when it should be down.

“We knew someday this was going to happen,” Emory said.