The original western approach to (and exit from) the upper deck of the bridge was a long ramp which began at Fifth and Bryant streets. There were also ramps for the upper deck on Rincon Hill at Fremont Street, and ramps for the lower deck at Essex and First Streets. The lower-deck ramps, utilized mainly by trucks, were terminal points for the lower-deck highway. Beyond them, the tracks of the bridge railway also left the lower deck, curving northward into a loop through the Transbay Terminal..
There were three original eastern approaches: a viaduct from the end of Cypress Street (State Route 17) in Oakland; a viaduct from the end of 38th Street (U.S. Route 50) at San Pablo Avenue in Oakland; and the Eastshore Highway which carried U.S. Route 40 along the shoreline of Albany, Berkeley and Emeryville.
When the Bay Bridge first opened, the upper deck carried three lanes of traffic in each direction and was restricted to automobiles only. The lower deck carried three lanes of truck and bus traffic on the north side. The middle of these three lanes was reversed according to the commuting direction by utilizing traffic lights, but with no divider. Two railroad tracks were built on the south side of the lower deck for the electric commuter trains of the Southern Pacific, the Key System, and the Sacramento Northern railroad, although train service across the bridge did not begin until January 14, 1939.
An overhead catenary supplied power to the Southern Pacific and Sacramento Northern trains at 1200 volts dc while a third rail at 600 volts dc was utilized by the Key trains. After 1941, only the Key System used these tracks. All railroad service on the bridge ended on April 20, 1958.

Henry Miller
Oakland