The victim was identified as 23-year-old Clayton Carlson of Palo Alto.
Caltrain struck and killed a pedestrian Thursday night.
At approximately 8:40 p.m., southbound train No. 190 hit a trespasser on the tracks about a quarter- to a half-mile north of the Churchill Avenue crossing in Palo Alto, according to Caltrain spokeswoman Christine Dunn. The cause of the fatality has yet to be determined.
The train was a local train and was stopping at all stations.
Emergency personnel arrived at 9 p.m. At 11 p.m., both tracks were open for travel, Dunn said.
This marks the 10th fatality on the Caltrain right of way in 2011. Last year, there were 11 fatalities.
Caltrain uses a "multifaceted approach" to prevent pedestrian fatalities, Dunn said, focusing on engineering, education and enforcement. More information on Caltrain’s efforts is available here.
A tweeter with the username @mikegee was on board and tweeted that the accident involved a fatality.
"I'll never forget the sound," he tweeted, "Ugh. People on the train are very casual about this. It's quite sad."
At 9:20 p.m., @mikegee uploaded the photo you see attached to this article via Instagram.
@mikegee said, "It was a person, no car involved. They were running straight into the front of the train."
Menlo Park Patch Editor Vanessa Castañeda and Bay City News Service contributed to this report.