The Associated Press
An amphibious craft is salvaged from the Delaware River in Philadelphia on July 9, 2010. A tug boat pilot who was consumed by a family emergency when the barge he was steering crashed into a stalled duck boat filled with tourists, killing two Hungarian students, pleaded guilty Monday to involuntary manslaughter.

A federal wrongful death trial is set to begin over the 2010 deaths of two Hungarian students killed when a tugboat-guided barge slammed into their sightseeing boat on Philadelphia's Delaware River.

A judge on Monday will consider a request by tug operator K-Sea Transportation and duck boat operator Ride the Ducks to limit their liability in the case to about $1.8 million -- the combined value of the two vessels.

Twenty-year-old Szabolcs Prem and 16-year-old Dora Schwendtner died when the 250-foot barge ran over the 33-foot duck boat. Thirty-five others were rescued.

The tug boat's pilot was sentenced in November to a year in prison after pleading guilty to the maritime equivalent of involuntary manslaughter.

Prosecutors said he was on his cellphone amid a family emergency.