During the next year, the Transbay Terminal was rebuilt into a bus depot. The tracks were removed and replaced with pavement for use primarily by the buses of the publicly owned successor of the Key System, AC Transit. All lines were operating from the rebuilt terminal by , and Greyhound service was added on . In 1971 Amtrak started running buses into the Transbay Terminal from the Southern Pacific's 16th Street Station. Bus service thrived until late 1974, when BART's Transbay Tube opened. Many people preferred BART over AC Transit. The tube didn't run through the terminal, resulting in its decline. Homeless people noticed the dropping commuters and took the chance to inhabit it.