The Old Town Transit Center was built in the early 1990s, and San Diego Trolley's North/South Line was extended here on June 16, 1996. In November 1997, the line, renamed the Blue Line, was extended into Mission Valley. When the Green Line service was introduced with the opening of the Mission Valley East extension on July 10, 2005, the Blue Line's northern terminus was pushed back to this station, which also served as the Green Line's western terminus. During a system redesign on September 2, 2012, as part of the Trolley Renewal Project, MTS extended the western terminus of the Green Line from this station to 12th & Imperial Bayside Terminal and shortened the Blue Line's northern terminus to America Plaza. The Special Event Line was eliminated; instead, the Green Line will add cars and offer more frequent service to Petco Park, San Diego Convention Center, SDCCU Stadium and Viejas Arena at San Diego State University when necessary.
Service
Commuter and intercity rail
The Old Town Transit Center hosts passenger trains operating on Amtrak's Pacific Surfliner intercity rail route and on the COASTER commuter rail line. Of the 22 weekday AmtrakPacific Surfliner trains operating in San Diego, 18 of them stop at the Old Town Transit Center, though the Surfliner trains operating at Old Town do not offer checked luggage service, and stop at Old Town to board passengers or detrain passengers only, respectively. Amtrak ridership at Old Town Transit Center has exploded over the last two years. In Fiscal Year 2011, there were just 22,867 boardings and detrainings at Old Town. In Fiscal Year 2012, boardings and detrainings at Old Town rose to 61,118, a 167% increase over FY2011. As of Fiscal Year 2013, the Amtrak ridership figure has continued to rise, to 135,749 boardings and detrainings, a further 122% increase over FY2012. Of the 74California stations served by Amtrak, the Old Town Transit Center was the 25th-busiest in Fiscal Year 2013, boarding or detraining an average of approximately 372 passengers daily.
San Diego Trolley
Old Town Transit Center is also a light rail station on the San Diego Trolley's Green Line. This station originally served as that line's terminus, until a system realignment on September 2012 extended the Green Line though Old Town to Downtown San Diego. Once the Trolley's Mid-Coast extension is completed, the Blue Line will be re-extended through this station to serve the University City area, and so the Blue Line will once again serve Old Town by approximately 2021. In July 2015, a 30-year naming rights agreement between MTS and UC San Diego Health was announced; as a result of this agreement, the Blue Line will be renamed "UC San Diego Blue Line" and the Old Town Transit Center will become "Old Town UC San Diego Health South".
There are four tracks; two tracks are designated for the San Diego Trolley services, while the other two tracks are used for COASTER, Amtrak, and BNSF freight service.