Blue Line (San Diego Trolley)

During a system redesign which took effect on September 2, 2012, Blue Line service between America Plaza and Old Town was discontinued, making America Plaza the Blue Line's northern terminus.[11] Blue Line trains traveled between America Plaza to San Ysidro on a regular 15 minute frequency, with a 7+1⁄2 minute frequency during weekday rush hours.[11][12] Blue Line service to Old Town was reinstated once the Mid-Coast trolley extension to UC San Diego was completed.[13] UC San Diego Health paid $30 million to rename the route the UC San Diego Blue Line in 2015.[14]

To accommodate the new Siemens S70 models and allow for their use on the line, the Blue Line stations needed to undergo renovation, although this was done over a period of five years to prevent the disruption of operation of the Trolley.[15] The project to renovate the stations, called the Trolley Renewal Project, began in fall 2010.[16][17] After beginning operation on the Green Line in 2011 and on the Orange Line in 2013, low-floor Siemens S70 LRVs began operation on the Blue Line on January 27, 2015.[18] Renovation of rail track and the final eleven Blue Line stations was completed in late 2015.[19][20]

The Mid-Coast Corridor Transit Project is an 10.9-mile (17.5 km)[4] extension of the Blue Line from the Old Town Transit Center north to La Jolla Village, University of California, San Diego and University City.[21][22] Ridership is projected at 34,700 trips in 2030.[23] The extension primarily follows the right-of-way of the Coaster and Interstate 5, with an elevated deviation around the UCSD area. MTS estimated construction costs of $2.1 billion.[23] An aim of the extension is to decrease demand for parking on the UCSD campus while providing direct trolley access to Westfield UTC, a popular shopping mall. The existing SuperLoop BRT Shuttle (Routes 201/202) provides transit in and around the UTC area from the nearby Trolley stations.[24] Testing of the line began in June 2021,[25] and it opened to revenue service on November 21, 2021.[9]

The Mid-Coast Corridor Transit Project was done in conjunction with the North Coast Corridor project, which upgrades the LOSSAN Corridor further to the north. Both projects build upon the original right-of-way of the Surf Line, which was built in the 1880s as the original railway from Los Angeles to San Diego.