Intruder on the tracks delays BART trains

An outbound train leaves the platform at the Glen Park BART station in San Francisco, CA, on Thursday, December 18, 2014. An outbound train leaves the platform at the Glen Park BART station in San Francisco, CA, on Thursday, December 18, 2014. Photo: Michael Short, Special To The Chronicle Buy photo Photo: Michael Short, Special To The Chronicle Image 1 of / 1 Caption Close Intruder on the tracks delays BART trains 1 / 1 Back to Gallery

BART was recovering from 20-minute delays Friday morning after a person was reported to be on the tracks between the Civic Center and 16th Street stations in San Francisco — the fourth intruder to breach the system’s rails in nine days.

Officials sent out an alert citing police activity and mechanical issues as the cause of the delay, but train announcers told passengers that there was “unauthorized personnel on the tracks,” according to multiple posts on social media.

Just before 8:30 a.m., drivers announced on trains that a person had been taken into custody, but delays were likely to persist.

Friday’s incident is just the latest in a string of similar occurrences. On Wednesday a man was arrested after walking along the trackway between the Richmond and El Cerrito del Norte stations. On Tuesday, a train struck and killed a person who was on the tracks near the North Berkeley station going in the Richmond direction. The death prompted the closure of the station for two hours.

Last week, police arrested a person on the tracks near San Francisco’s Civic Center station, which also caused major delays.

Kale Williams is a San Francisco Chronicle staff writer. E-mail: kwilliams@sfchronicle.com Twitter: @sfkale