Jerry Rivera, the switchman killed Wednesday when a truck rammed into the train on which he was riding, was "a good man and a good dad," his sister said today.

Rivera, 33, had worked for the railroad for about four years, Sonya Rivera said.

He leaves behind three daughters, teenager Ariana and two younger ones, Jessica, 9, and Katie, 5.

Wendell Cox, 47, of Bedford Heights, Ohio, the driver of the Freightliner truck that struck the train, was released from North Suburban Medical Center and quickly arrested for careless driving causing death. He is in the Adams County Jail.

Drugs and alcohol aren't suspected in the crash.

Rivera graduated from Rocky Mountain High School in Fort Collins and most recently had been living in Denver, Sonya said.

"His daughters were really Daddy's little girls," Sonya said.

"The last thing he told me was that he was going to bring his daughters to the park to throw bread at the geese."

He did so, and shortly after that boarded the fateful train.

He attended college for a short while to learn how to be a medical assistant, but he dropped out to take care of his daughters, she said.

Rivera was found pinned under the train after the tractor-trailer plowed into it, the North Washington Fire Protection District said.

The crash occurred about 7 p.m. A 2006 Freightliner tractor-trailer was traveling west on East 66th Avenue in an industrial area crisscrossed by railroad tracks, about a half mile south of Interstate 76.

A Union Pacific locomotive with three rail cars was going slowly in reverse, north on a track near Franklin Street, troopers said.

The tractor-trailer then hit the rail car where Rivera had been standing at the rear, trooper Gilbert Mares said.

The impact sent the tractor-trailer onto its side, injuring Cox.

Melissa Rivera, who had Kate, 5, with Jerry, said, "He was a really good person with a big heart. He would do anything for his girls. They were the most important thing to him."

Funeral arrangements haven't been set.