Ever wondered what it feels like to be deep beneath the bay? Today, we explore the Transbay Tube a marvel of engineering. It ferries millions between Oakland and San Francisco.
September 16, 1974, marked a historic day. The Transbay Tube opened for passenger service. It was unlike anything the world had seen. This 3.6-mile tube was the longest immersed tube until 2010. People were mystified by the idea of a structure 135 feet below water.
Kenny Meyers, a budding actor, power washed the Tube in 1973. He prepared it for its public debut. Meyers never left BART and retired after 48 years. He recalls his interview. The supervisor asked if he had jeans. Meyers nodded and was told to wear them the next day.
Few have seen the Tube where it lies. Specially trained divers navigate the zero-visibility waters. They encounter waves of sand deep holes and mounds of rock. Sharks whales and fish float above this engineering feat.
When riding BART from Oakland to San Francisco you zoom through this world at 70 miles per hour. Most passengers are on their phones. Children are often mesmerized hoping to see a shark or seal. The Tube isn’t translucent so you wouldn’t see anything anyway.
Back when the Tube opened Meyers played a prank. A train stopped near a vent. Meyers made a swimming face against the vent. Children screamed thinking he was swimming underwater.
Meyers said people treated the Tube like a Disneyland ride. They rode it just for fun. He clarified that there’s no Starbucks down there.
The Tube has two bores with one trackway each. Trains go west from West Oakland through the right bore. They go east from Embarcadero through the left bore. Between the bores are upper and lower galleries. Workers use these for access ventilation and utilities. They sometimes use narrow golf carts or bicycles.
BART staff enter through five-story vent structures. It’s dark and grimy due to brake dust. Fans circulate air making it blustery. When trains pass wind blasts through the gallery doors. It creates a suction effect. Meyers said the Tube has a specific smell he can’t place.
The Tube isn’t Disney but it has magic. You feel like you’re passing through giant smoke rings. George Lucas filmed a THX 1138 scene in the Tube in 1971. Robert Duvall crawls horizontally through it.
Emperor Norton proposed an underwater rail tunnel in 1872. He commanded Oakland and San Francisco to survey its practicability.
In 1947 a joint Army-Navy Commission recommended an underwater Tube. This would relieve Bay Bridge traffic.
Construction began in 1965. The Trans-Bay Constructors aimed to place two Tube sections a month. Each of the 57 sections averaged 330 feet long. They were fabricated at Bethlehem Shipyards. Then they were towed into the bay and sunk. Each segment was weighted with 500 tons of gravel ballast. Divers directed the segments into position.
The last section was placed in 1969 near Yerba Buena Island. In August 1973 the first train traveled through the Tube. By 1974 the original BART system was complete.
During the Loma Prieta earthquake in 1989 Donna Wilkinson drove a train through the Tube. She didn’t even feel it. The Tube absorbed the shock. BART ran 24-hour service while the Bay Bridge was out.
The Earthquake Safety Program began in the early 2000s. It retrofitted the Tube for a major earthquake. Jim Dunn BART’s Chief Engineer instigated it. Chuck Bernardo said retrofitting was like open heart surgery every night.
The Tube is designed to flex with ground motions. There are seismic joints at both ends. A steel liner was added on the Oakland side. The steel plate handling machine was crucial. Workers often worked 12-hour shifts six days a week.
The Transbay Tube is an underwater steel structure prone to rust. BART uses a cathodic protection system. Anodes sacrifice themselves to protect the Tube.
Maansii Chirag Sheth oversees the cathodic protection system. Replacing anodes requires specialized contractors and equipment.
The Tube could be under the Bay forever. BART plans to operate up to 30 ten-car trains per hour. This will increase capacity and shorten wait times.
The Transbay Tube stands as a testament to human ingenuity. It is a vital link connecting communities.