The operator of the Pittsburg/Bay Point bound train reported the incident shortly after 10 p.m., spokesman Jim Allison said.
Emergency crews discovered the person on the trackway and the pedestrian was transferred to Highland Hospital. The extent of the injuries was not yet known.
The station reopened at 10:50 p.m. and trains were being single-tracked as of 11:30 p.m.
Riders should expect delays of up to 30 minutes in east- and westbound trains on the Pittsburg/Bay Point-SFO line, Allison said.