Metro-North officials were investigating what caused an accident in the Stamford rail yard that killed a veteran conductor Wednesday.

Robert Ard Jr., a 46-year-old father of two daughters ages 11 and 13, was lining up cars for the Wednesday morning run to Grand Central Terminal in New York City when he was run over by one of the coaches. "The accident is still under investigation," said Dan Brucker, a spokesman for Metro-North. Brucker said Ard, of Fairfield, was directing the addition or subtraction of cars for trains bound from Stamford to New York.

"He had been in radio contact with the engineers," Brucker said. "Then contact was lost. They found his body near the track."

The Connecticut Post reported Thursday that Ard complained three weeks ago about how overworked his night crew was.

Brucker said the fatal accident was the first at the Stamford yard. However, on July 18, 1997, James Robert Avery, a Metro-North flagman from Hamden, was killed when a Metro-North locomotive hauling a flatbed car from Stamford to Mount Vernon, N.Y., struck him just west of the Stamford yard.