CASTLE ROCK, Colo. -- The family of a Castle Rock teenager hit by a train 18 months ago have been billed for the accident by the railroad, but Union Pacific said the bill was the result of a "clerical error."

The family of Missy Martin received the bill for almost $600 on the same day they helped break ground for a $5 million vehicle flyover that will allow vehicles to bypass the dangerous train crossing. A day later, Union Pacific said the bill was sent in error. The company didn't explain why the bill was sent 18 months after the accident, but said it was a mistake.

More than 17,000 vehicles cross the railroad tracks every day at Front Street, according to Castle Rock officials. The current crossing has only crossing arms on each side of the track. The new flyover will allow vehicles to go over the railroad tracks without stopping.

On Nov. 12, 2002, a car (pictured, left) driven by Castle Rock high school student Missy Martin was broadsided by a freight train after it stalled on the tracks while she was on her way to school. Martin was partially paralyzed in the accident.

Following the accident, officials asked trains using the track to slow down when traveling through town. But both Union Pacific and Burlington Northern Santa Fe Railway said the speed change would disrupt schedules throughout their systems.

Union Pacific said slower trains would block crossings longer, creating more problems without improving safety.

Missy's father, Dave Martin, was on hand Monday during the groundbreaking and said his daughter is still recovering from her injuries.

"It's a struggle, I mean she's going a little bit better every day," said Martin. "It's been a long time coming."

The company that owns the train that crashed into Missy Martin wants the family to pay for the railroad's loss and damages from the wreck.

Union Pacific Railroad mailed the Martin's family a bill for money Union Pacific Railroad said it lost as a result of the accident -- mostly from lost wages.

The family called the action by Union Pacific "outrageous."

Castle Rock officials said the $5 million cost of the flyover project will be financed by the city, but they plan to ask Union Pacific to help with the construction costs.

The project is expected to be completed this fall.