The Dumbarton Rail Corridor project provides a once in a century opportunity to construct a vital link that would support an expanded and integrated public transportation network throughout the greater Bay Area region, including coordinated heavy rail connections linking the San Joaquin Valley, Tri-Valley, East Bay and the Mid-Peninsula markets. A high-capacity state-of-the-art heavy rail artery along the Dumbarton Rail Corridor (Corridor) is needed to realize this objective.