|Restored 1900's streetcar|
|San Francisco Streetcar (author's collection)|
The three years of San Francisco Bay bridge construction started in 1933 and cost $77 million dollars to build. Prior to the bridge's completion there had been electric interurban railroads on both sides of the bay. With the bridge completed in 1936, it was time to connect the east bay with the city of San Francisco with a rail track directly across the bridge. A new page in history was in store for the Bay Area electric trains.
Actually, the early designers of the bridge specifically made space along the south side of the lower deck for two tracks. It was a given that the bridge would handle electric train traffic. The rail facilities for the bridge line was financed with $15 million of bonds through the Reconstruction Finance Corporation. This line was put under the direction of the California Toll Bridge Authority. The line extended just under seven miles from the east side of San Francisco Bay to a terminal in San Francisco.
|Oakland Bay Bridge under construction|
When construction started on the tracks, which was after the roadway sections were completed, it was evident that a multi-voltage system would have to be installed. How to deliver different voltages on the bridge was the question. Several options were outlined and studied. Some consisted of multi-voltage overhead lines plus a third rail. In other words, overhead lines that would be delivering different voltages to different railways. Quite complicated and expensive to build and operate. The option chosen was a combination third rail with an overhead line to deliver one voltage. The third rail was to deliver 600 volts and the overhead wire 1,200 This option was the less costly and also made it easier to bill each rail line for the power used..
The next step in planning was to devise a routing system for all three lines which would bring them together into the bridge yards. The Sacramento Northern cars were using the Key System tracks making that part much easier. The Interurban Electric was eventually rerouted to a curving elevated track going over the Southern Pacific mainline tracks and joining existing tracks in Emeryville.
|San Francisco-Oakland Bay Bridge|
As far as the history of railways is concerned, the entire control system was, for the era, was fairly advanced in design. Sensors were placed on the rails at various intervals. The sensors were able to detect passing trains and send coded information to receivers on the train cars. The train receivers just transferred the information into the control panel of each train. The control panel then adjusted speed limits.
Another interesting and very necessary item was the "train describer". This feature of the control system identified every destination for every train. When a train left the San Francisco station for, example, it's destination would be sent to the Bridge Yard Interlocking Tower. The operator in the tower would then know how much time would elapse before the train entered the interlocking yard area. The "train describer" would be able to show the destinations of the first three approaching trains as well as the presence of up to seven additional trains behind those. It was very important to know which trains were where at any given time. With this information it was then possible for the tower operator to plan all of their routes accordingly. This was necessary since trains were enroute to many different places after crossing the bridge. The "train describer" was also very helpful at the west end of the San Francisco-Oakland Bay Bridge because the Key System trains had to be separated from the other two lines because it was using a separate terminal lead track. all of this may sound a bit confusing but when three different lines were all crossing the bridge, sorting them all out was absolutely necessary. Very similar to what an air traffic controller does today. As a historical side note, it's interesting to learn that all of the train designations for the Interurban Electric line were in numerals. The Key System trains all were assigned letters and the Sacramento Northern cars were all assigned the letter "N". These identifiers were placed on the left front end of the car on a metal disc.
|Present day San Francisco streetcar (author's collection)|
The San Francisco Terminal building was planned as far back as 1932. The structure selected was a state sponsored plan and was built was facing Mission Street between First and Fremont Streets, The cost was about $2.3 million. The first "official' test run for the bridge crossing was held on September 23, 1938. a group of Southern Pacific and Interurban Electric officials went on a special train from Oakland Pier. They then transferred to a Key System car for the trip across to San Francisco. The Key System car was used in this instance because at that time the power system that was energized was only at 600 volts of overhead power. This was about the only time that the Key System ran over the bridge with it's pantograph raised for power. Several more test trips over the bridge occurred over the next several weeks using various configurations with baggage cars, etc. In the middle of January 1939 all testing was completed and the cross bay interurban service was ready to start carrying passengers. As with all new systems, some problems emerged during the first several weeks and months. Some were of a technological nature and others were simply due to the inexperience of some trainmen. As is always the case, the problems were eventually remedied and the new cross bay train route was a great success.