BART Silicon Valley Phase II Extension

Alignment

Phase II runs approximately 6 miles from the Berryessa/North San Jose Station (end of Phase I) south through downtown San Jose and west to a terminal at Santa Clara, near the Caltrain station and SAP Center. The extension is entirely underground, with four new stations: Downtown San Jose, Diridon, West San Jose, and Santa Clara.

The tunnel runs beneath First Street and Santa Clara Street in downtown San Jose before swinging west along the Guadalupe River corridor. The two tunnel boring machines (nicknamed “Elsie” and “Cleo”) began digging in 2023 from the Berryessa end heading south.

Updates

2026-03 — TBMs reach midpoint under downtown San Jose

Both boring machines have crossed the midpoint of their drives, having mined past the planned Diridon Station box. Excavation of the Downtown San Jose station cavern is approximately 60% complete.

2025-09 — Tunnel boring on schedule despite soil challenges

VTA reported that while crews encountered unexpectedly soft alluvial soils near the Guadalupe River crossing, the TBMs remain within the project schedule. Grouting operations stabilized the alignment.

2024-11 — Additional federal funding secured

The Federal Transit Administration approved a Capital Investment Grant amendment adding $1.4 billion in federal funds, bringing the total federal share to approximately $4.7 billion and reducing uncertainty around the project’s financing plan.

2023-04 — Tunnel boring commenced

The first TBM launched from the Berryessa portal, marking the start of the underground construction phase. A ceremony was held with VTA board members and the Mayor of San Jose.