San Diego’s Mid-Coast Trolley Extension Project Advances
Testing has officially begun on the $2.1 billion, 11-mile Mid-Coast Extension of the UC San Diego Blue Line, which is scheduled to open in November 2021.

Testing has officially begun on the $2.1 billion, 11-mile Mid-Coast Extension of the UC San Diego Blue Line, which is scheduled to begin service in November 2021.
San Diego MTS
Transportation leaders and transit advocates from around the San Diego region gathered on June 29 to witness the first-ever Trolley on the Mid-Coast Extension of the UC San Diego Blue Line.
The milestone signifies that train testing is beginning and that the San Diego Association of Governments (SANDAG) is officially transferring responsibility of the $2.1 billion project to the San Diego Metropolitan Transit System (MTS) for operations.
“This is an important day,” said Nathan Fletcher, MTS board chair and chair, San Diego County Board of Supervisors. “We get the keys to Mid-Coast and it’s all-systems-go for testing our Trolleys on the tracks. The public will see more and more of San Diego’s famous red Trolleys testing on these tracks over the next several months.”
The Mid-Coast Extension of the UC San Diego Blue Line Trolley is a priority project for SANDAG and will have a transformative impact on regional transit connectivity. The project will expand the current Trolley network to provide a one-seat ride from the U.S./Mexico Border all the way north to the University community. The extension will connect the two largest employment centers in San Diego — the University area and Downtown San Diego — which supports 75,000 students, faculty, and staff, and provide healthcare access to the VA San Diego Healthcare System’s 84,500 veterans.
Major construction for the 11-mile Trolley extension began in 2016, and is scheduled to begin service in November 2021, according to MTS. Key dates for testing and training on the extension include:
June 29 - September 10: MTS Rail Activation Committee will test train operation aspects of the system including vehicle and system interface testing, traction power, braking, speed, and travel time verification.
September 10: MTS Rail Activation Committee testing is anticipated to be complete.
September 11: the six north-end stations are anticipated to be complete and MTS will take on security, facilities, and maintenance for those stations and the full alignment.
September 17: MTS will begin training operators and supervisors on the full 11-mile extension.
November 21: MTS is planning to open the full alignment for revenue service.
To support the extra service, MTS has added 45 new Trolleys built by Siemens Mobility and partially funded by TransNet, the region’s half-cent sales tax for transportation projects. In addition, MTS has added 128 new positions including train operators, security, maintenance, and IT personnel to manage the extension.
Watch a news conference about the first Trolley on the Mid-Coast Extension below.
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