Editing Altamont Corridor Express (section)

=== Service expansion ===
[[File:Santa Clara station 0937 11.JPG|thumb|left|ACE service to Santa Clara station began in 2001, was suspended in 2005, and returned in 2012.]]
The original service used two trainsets, each with four bilevel coach cars, for a total seated capacity of 1,120 passengers in each direction daily. In September 1999, less than a year after opening, the service reached 1,000 daily riders per direction, near full capacity.<ref name="subwaynut">{{cite web |url=http://subwaynut.com/california/ace/ |title=Altamont Commuter Express on the SubwayNut |publisher=Subway Nut |date=July 10, 2013 |first=Jeremiah |last=Cox}}</ref>

With that success, the agency wanted to add additional runs. To enable more trains on the line, ACE funded $3 million in track improvements,<ref>{{cite web |last=Cabanatuan |first=Michael |date=November 16, 1999 |title=ACE to Add Third Morning Train / Pleasanton-to-San Jose service will begin by Feb 15 |url=http://www.sfgate.com/bayarea/article/ACE-to-Add-Third-Morning-Train-2896900.php |access-date=August 29, 2016 |newspaper=San Francisco Chronicle}}</ref> but the limited amount of equipment allowed ACE to add only a morning "[[short turn]]" run between San Jose and Pleasanton. This "turn-back train" started service on February 21, 2000, and gave Pleasanton and Fremont a third inbound train to alleviate the crowding on the two earlier trains.<ref>{{cite web |archive-url=https://web.archive.org/web/20000511182101/http://www.acerail.com/history.html |archive-date=May 11, 2000 |url=http://www.acerail.com/history.html |title=History |publisher=San Joaquin Regional Rail Commission}}</ref> Even with the added capacity, by early 2001 ACE was regularly carrying more than 700 daily standees.<ref name="bolster">{{cite news |archive-url=https://web.archive.org/web/20011108161652/http://acerail.com/herald-news-3-12-01.html |url=http://acerail.com/herald-news-3-12-01.html |archive-date=November 8, 2001 |title=4th Ace train to bolster the fleet |first=Mike |last=White |date=March 12, 2001 |newspaper=Press Herald |via=San Joaquin Regional Rail Commission}}</ref>

ACE purchased additional equipment, allowing the "turn-back train" to operate to Lathrop/Manteca station, nearly the full length of the route, beginning on March 5, 2001; trains also began stopping at [[Santa Clara Transit Center|Santa Clara station]].<ref>{{cite news |last=Bott |first=Fran |date=March 1, 2001 |title=Third ACE train ready to roll |newspaper=The Record |url=http://acerail.com/stockton-news-3-1-01.html |archive-url=https://web.archive.org/web/20011108152441/http://acerail.com/stockton-news-3-1-01.html |archive-date=November 8, 2001 |via=San Joaquin Regional Rail Commission}}</ref> Although the third train added 560 seats in each direction, it brought an immediate increase of 380 daily riders.

ACE then planned to add a fourth round trip later in the year, with fifth and sixth round trips by 2006.<ref name="bolster" /> However, by late 2001, the deepening [[dot-com bubble|dot-com recession]] was severely hurting ridership, and expansion plans were put on hold. On June 30, 2003, the ACE JPA was dissolved in favor of a Cooperative Services Agreement between the three member agencies.<ref name="acehistory" />

On January 6, 2003, ACE introduced the Stockton Solution Shuttle, allowing Stockton passengers to use the ACE trip which terminated at Lathrop/Manteca.<ref name="subwaynut" /> The trip was extended to Stockton on August 1, 2005. At that time, service to Santa Clara was suspended to allow for the construction of a second platform and pedestrian tunnel at the station.<ref>{{cite web |url=http://www.acerail.com/main/documents/Schedule2.pdf |archive-url=https://web.archive.org/web/20051126105940/http://www.acerail.com/main/documents/Schedule2.pdf |archive-date=November 26, 2005 |title=Schedule Changes will be effective August 1, 2005 |publisher=San Joaquin Regional Rail Commission |date=August 1, 2005}}</ref>

On August 28, 2006, ACE added a fourth round trip, which operated midday using one of the existing trainsets.<ref name="acehistory" /> On November 7, 2006, San Joaquin County voters approved a 20-year extension of Measure K.<ref name="measureK" /> Suffering from reducing funding due to the [[Great Recession]], ACE cut the lightly used midday trip on November 2, 2009.<ref name="subwaynut" /> On May 14, 2012, ACE restored service to Santa Clara station.<ref name="bra" /><ref>{{cite web |archive-url=https://web.archive.org/web/20120508074128/http://www.acerail.com/Home.aspx |archive-date=May 8, 2012 |url=http://www.acerail.com/Home.aspx |title=ACE {{!}} Altamont Corridor Express |publisher=San Joaquin Regional Rail Commission}}</ref> On October 1, 2012, a fourth rush-hour round trip was added, running approximately one hour after existing trips.<ref name="subwaynut" />