Construction Begins on San Diego Trolley Extension

Mid-Coast corridor, transit project, extend trolley service, northern sections, San Diego


Construction is under way on the Mid-Coast Corridor Transit Project, which will extend trolley service to northern sections of San Diego.

Construction is under way on the Mid-Coast Corridor Transit Project in San Diego, which will extend trolley service to northern sections of the city when completed in 2021.

A $1 billion grant from the Federal Transit Administration was approved in September, clearing the way for construction. A groundbreaking ceremony was held Oct. 22 for the $2.17 billion project, a 10.9-mile double-track alignment that will extend San Diego’s existing trolley system from the San Diego Transit Center in Old Town to University City.

“University City is home to the University of California, San Diego [UCSD], and as a major employment and residential center, it is considered the city’s ‘second downtown,’ said Reddy Chidananda, project manager for WSP. “Although the Mid-Coast Corridor is currently served by bus transit, the existing transit system does not offer the level of service needed to meet the region’s goals for mobility, accessibility, reliability and efficiency.”

Reddy Chidananda

WSP is the lead engineering and environmental consultant to San Diego Association of Governments (SANDAG) and San Diego Metropolitan Transit System on the Mid-Coast Corridor Transit Project. The firm is also the designer of record, responsible for advancing the project from conceptual engineering through final design, including track and systems design and operations analysis, station design, traffic engineering, civil and utilities design, and structures design.

“Because it operates in a dedicated right-of-way, the extension will provide greater reliability and faster travel times and travel speeds than those provided by the bus network that currently serves the corridor,” Chidananda said. “The speed and reliability of bus service is constrained by roadway congestion and will further decline as population and traffic congestion continue to increase in the corridor.”

The extension includes nine stations—four at-grade and five aerial—located at Tecolote Road, Clairemont Drive, Balboa Avenue, Nobel Drive, VA Medical Center, UCSD West, UCSD East, Executive Drive and the Westfield University Town Center. The project also includes five park-and-ride facilities providing a combined 1,170 parking spaces.

“Transit passengers will be able to use the trolley service to travel from University City to the San Ysidro Transit Center at the U.S.-Mexico border,” Chidananda said.

A California First

The project includes nearly four miles of elevated guideway through University City, one of the most densely populated communities of San Diego.

Mid-Coast corridor, transit project, extend trolley service, University California-San Diego Campus


The extension includes nine stations, including the aerial Pepper Canyon Station on the University of California-San Diego campus.

“The project includes a segment of viaduct more than a mile long that will be constructed using the pre-cast ‘tub’ girder construction method, which has never been implemented on a California transportation project,” Chidananda said.

The project requires close coordination with UCSD’s capital development staff to make sure it is compatible with the campus environment and long-term development plans.

“Construction access and staging has to be carefully planned around the school’s calendar, particularly special events,” Chidananda said. “Our construction must take into account construction projects that the campus is undertaking during the same time frame.”

A section of the project will be constructed parallel to existing railroad operations, including commuter and intercity passenger rail, which required collaboration with North County Transit District and Amtrak.

“Risk-based hazard analyses were performed to identify and mitigate site-specific risks, resulting in economical and maintainable solutions accepted by the rail operators and safety regulators,” he said. Reconstruction of some railroad tracks as part of the project will accommodate the light rail transit system.

Computer simulations of railroad operations along this corridor were developed to reflect various stages of the construction, while also taking into account other projects affecting railroad capacity along the corridor.

Mid-Coast corridor, transit project, extend trolley service, North to Westfield University Town Center


When completed in 2021, the trolley line will extend nearly 11 miles north to the Westfield University Town Center.

“Given the 11 mile-footprint of this project, which will have concurrent construction activities throughout, maintaining the required spectrum of technical expertise and responding to requests at a moment’s notice will be challenges, but ones we are prepared to overcome,” Chidananda said.

Since the Beginning

The Mid-Coast Corridor Transit Project was first proposed in the late 1980s, with environmental clearance and conceptual design of the project taking place in the 1990s and continuing through 2001. WSP joined the project when the final design effort began in 2007.

WSP was responsible for preparing the National Environmental Policy Act and California Environmental Quality Act documents required for environmental approval of the project. This included preparation of the alternatives analysis, draft and final supplemental environmental impact statement/subsequent environmental impact report (SEIS/SEIR), and the SEIS/Supplement to the SEIR for impacts to the federally endangered San Diego fairy shrimp.

WSP also coordinated preparation of the resource agency permits and provided land-use, cost-estimating, financial and travel forecasting services and preparation of materials in support of the preliminary engineering and engineering applications.

“It was quite meaningful to our team to have the opportunity to help SANDAG bring this project through its final design and environmental clearance, successfully addressing every challenge that arose during the process,” Chidananda said. “Our team is now excited to continue to support SANDAG through construction of this important regional project.”

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