Caltrain spokeswoman Christine Dunn said shortly before 9 a.m. that the delays would likely continue for another hour as Caltrain works to get trains back on schedule.
At about 5 a.m., northbound train No. 101 struck a car that had apparently been left on the tracks at Mary Avenue, Dunn said.
There were 35 passengers on the train, but no one was injured.
Both north- and southbound tracks were reopened at about 8:40 a.m.
A bus bridge was set up between the Mountain View and Sunnyvale stations during the disruption.
