Transit Featured Project

SFMTA Third Street Light Rail Central Subway

Project Description:

The San Francisco Municipal Transportation Agency (SFMTA) plans to extend the current light rail, subway system and link up the south and eastern part of the City to the downtown and Chinatown areas. The project involves deep tunneling underneath the downtown San Francisco commercial business district, crossing and connecting existing Bay Area Rapid Transit (BART) and Muni rail systems into Chinatown. The new extended subway will have three new underground stations with passenger boarding platforms, extended wayside and guideway, and control systems, and one surface station for this new subway line.

Project Value:

$1.58 Billion




As a key member of the general engineering team, Cornerstone provided the core computer aided design and drafting services including the setting up of computer aided design and drafting (CADD) operation standards and assisting with establishment of the Quality Control Plan. Cornerstone was responsible for coordination of the input of 32 design disciplines and synchronizing the data into a uniform standard. Our CADD team also produced rendering including 3D modeling drawings to present the engineering and architectural concepts for public presentation. We also worked closely with the project engineers to provide designs for excavation support and building protection in addition to the typical CADD operations for civil, structural, underground, architectural, mechanical and electrical systems. Besides CADD coordination, Cornerstone team provided cost estimating, scheduling, structural engineering support, and document control services. The two-phase preliminary engineering design was extremely complex, as the subsurface conditions were unstable and the construction activity could have an impact on the structures above ground. Cornerstone performed building condition assessments, design studies and analysis, and assisted with the development of high level detailed engineering specifications, project schedule and document control.