This is the only rail line that crosses the San Francisco bay, the middle portion of which was abandoned in 1982. Union Pacific continues to operate the east side of the line, from Newark Junction to the west, to serve industrial customers. Caltrain owns the other side from Redwood Junction to the east, usually using it for storing work train equipment. Caltrain was chosen to operate on the line for future commute service. This project would add four stations to the Caltrain system: Union City, Fremont-Centerville, Newark, and Menlo Park/East Palo Alto. The two swing bridges along the line would have to be replaced. About 33% of the bridge collapsed due to an arson fire in 1998. This project is currently facing financial difficulties with many asking if it is really needed. Construction is scheduled to start in 2009 after a 30-month environmental review, and begin service in 2012.
Thanks to Paul Carr for contributing information about this route.