South San Francisco station (Caltrain)

Prior to the new station's opening, a southbound train holds outside the station while passengers board a northbound train

The previous station was built before the Bayshore Freeway[7] and retained many of the aspects common to older, unmodernized stations along the Peninsula Commute: the platforms were not accessible-compliant, and riders seeking to board a northbound train had to wait for the train to come to a complete stop before crossing the southbound track to a narrow boarding platform between the tracks.[13] This necessitated the so-called "hold-out" rule (GCOR 6.30)—if a train was stopped for passengers, an approaching train on the other track had to wait outside the station.[14][15] In 2012, a southbound Baby Bullet express train passing through the station narrowly avoided striking passengers for a northbound train stopped at South San Francisco. The Baby Bullet express did not have a scheduled stop at the station and had ignored the hold-out rule.[16]

South San Francisco was the only hold-out rule station with regular service on weekdays (Broadway is open only on weekends, Atherton was open only on weekends until its closure in 2020, and College Park only has limited weekday service tailored to Bellarmine Prep opening and closing times), making it a bottleneck for rail traffic.[4] The hold-out rule was finally lifted for South San Francisco when the new station platform opened in September 2021.[4]

In 1998, the City of South San Francisco prepared a concept plan to relocate the station southward so that trains would stop south of the Grand Avenue overpass in order to improve bus and pedestrian access to the station. This would allow buses currently stopping on Airport Boulevard (west of the Bayshore Freeway and the station) to directly service the station and open up access from the east for employer-provided and Commute.org shuttles.[6][17]

In 2012 Caltrain and the City of South San Francisco began work on a Downtown Station Area Plan to redevelop the area around the station and make it easier to reach downtown from the station. The plan called for updating the station by renovating the southbound platform and extending it south, and building a new northbound platform to eliminate the "hold out" rule and to be accessible-compliant. It included a new 700 foot (210 m)-long island platform (between northbound and southbound tracks), a bus and shuttle drop-off area on Poletti Way, and an accessible-compliant pedestrian underpass to the new platform to connect with East Grand Avenue/Poletti Way (on the east) and Grand Avenue/Airport Boulevard (on the west).[5] The planned west entrance also featured a new pedestrian plaza at the southeast corner of Airport Boulevard and Grand Avenue, on right-of-way previously used as a Caltrans storage yard.[18][19] A new pedestrian gate crossing at the northern end of the new platform would provide access to the existing parking lot.[20]

The plan was approved in February 2015[18] and was be funded by $49.1 million in funds provided by San Mateo County Measure A, a half-cent sales tax approved by county voters in 2012.[21] Peninsula Corridor Joint Powers Board contributed $4 million and South San Francisco contributed $9.2 million, including $3.3M to expand station property and remediate soil.[22]

Although construction was scheduled to begin in 2016,[23] the design was not finalized until December 2016,[5] and groundbreaking for the modernization project was held on November 6, 2017 in a ceremony attended by State Senator Jerry Hill and South San Francisco Mayor Pradeep Gupta.[22] The new station was projected to open in 2019,[5][23] but was delayed to August 2020 after planned underground utility relocation work was determined to be a prerequisite for construction of the new pedestrian underpass.[24] it was further delayed to summer 2021, then November 2021, and finally January 2022 due to the coronavirus pandemic.[3][5]

• 
  Platform construction, July 2018
• 
  Platform construction, December 2020
• 
  Underpass construction, December 2020