There were approximately 300 to 400 passengers on the train, No. 369, and no one aboard was injured in the collision, Caltrain spokeswoman Tasha Bartholomew said.
According to San Mateo County Transit Police, she said, a Nissan Altima rental car driven by an Indiana couple was traveling east at the intersection when it was struck. The car had been stopped on the tracks due to backed-up traffic in the area, she said.
The man and woman were visiting family in Palo Alto, she said.
Bartholomew said that, according to transit police, the woman, who was believed to be the driver, was killed and that the man managed to flee from the car. Transit police did not know whether the woman attempted to escape the car, she said.
A call to the San Mateo County Transit Police, which is a branch of the sheriff's office, was not immediately returned.
Caltrain service came to a complete halt in both directions, but at 7:46 p.m., tracks reopened in both directions at slow speeds. Earlier, southbound train No. 264 was turned around north of Palo Alto and made all local stops in the northbound direction, Bartholomew said.
As of 8:30 p.m., northbound Caltrain service through the South Bay was experiencing delays between 90 minutes to two hours.
The Santa Clara Valley Transportation Authority provided five buses for a bus bridge between the California Avenue and San Antonio Caltrain stations, Bartholomew said.
The San Mateo County Transit District and Bay Area Rapid Transit also honored Caltrain tickets to accommodate stranded travelers, she said.
Bartholomew said that Caltrain has "an ongoing commitment to improve safety on the railroad" and continues working with the VTA on grade crossing improvements throughout Santa Clara County.
Those improvements, she said, will make eight crossings safer for pedestrians, bicycles and automobiles by incorporating modified crossing gates, newly installed guardrails, fences, and pedestrian and emergency swing gates, among other features.
Charleston Road, where tonight's collision occurred, is among the eight Caltrain crossings included in the grade improvement project, Bartholomew said. Other crossings in Palo Alto that are part of the project include Churchill Avenue and East Meadow.
This was Caltrain's sixth fatality in 2011.
"No matter what the circumstances, it is always regrettable when a life is lost," Bartholomew said.
