Chapel Hill, N.C. — A memorial service was held Tuesday for a mother and son who were killed in a train-car collision last week at Southern Drive and Mount Willing Road in Efland.

Investigators said the fatal crash happened after Erin Brett Lindsay-Calkins, 26, drove under the crossing arms. Her Toyota was on the tracks when the train hit, and she and her 5-year-old son, Nicholas Lindsay, were killed.

Meanwhile, Lindsay-Calkins' 4-month-old daughter, Aven Brooke Lindsay-Calkins, has been released from UNC Hospitals, according to hospital spokesman Clinton Colmenares.

The mother, who had been married for just over a year, was on her way to a dentist appointment when the crash happened. She had left two hours early and wasn't in a hurry, according to her husband.

"I don't know how she was in that situation. I know that she pays attention when she drives and she had two babies in the car,” Michael Lindsay-Calkins said Saturday.

Erin Lindsay-Calkins worked at Duke's Center for Aging until she left to go on maternity leave. Nicholas attended Central Elementary School in Hillsborough.

“It's going to be hard, but I'm going to try to give (Aven) the best life I can," Michael Lindsay-Calkins said.

A spokeswoman for Norfolk Southern said the company has fielded 11 calls in the past year from people reporting problems with the crossing. A malfunction was reported in one of the cases in which a defective breaker needed repair, said spokeswoman Robin Chapman.

The other cases dealt with a broken light or gate, typically caused by drivers trying to cross the intersection during or after the warning lights and gate were triggered, according to Chapman.

North Carolina Department of Transportation spokesman Paul Worley said the state was unaware of any problems with the crossing. The last wreck at that crossing was in January 1980, he said.