Agency officials said train No. 366 struck a trespasser just after 5 p.m. near Brewster Avenue.
Caltrain spokeswoman Tasha Bartholomew said emergency personnel were on scene, and no injuries were reported to passengers onboard the train.
Passengers should expect delays.
Stay with ABC7 News for more on this developing story.
366 terminated— Caltrain (@Caltrain) February 14, 2017
268 -13 mins late @ HIL awaiting single tracking
370 -2? HPK
269 -16? MPK
273 -10? PA#Caltrain
Transit PD reporting NB track lear for resuced speed movement. Single tracking about to begin. #Caltrain— Caltrain (@Caltrain) February 14, 2017