San Francisco light rail to replace floppy disk control system

The San Francisco light rail system continues to rely on 3.5-inch floppy disks for its Automatic Train Control System, a technology implemented in 1998. Despite the city's proximity to Silicon Valley, operators must still manually load software into central units using these magnetic disks every morning.

While the system is noted for its reliability, the San Francisco Municipal Transportation Agency faces challenges regarding data loss risks on aging media and a shrinking pool of programmers skilled in 1990s-era languages.

To address this, the agency has entered a $212 million contract with Hitachi Rail as part of a broader $700 million modernization plan. The upgrade aims to replace the disk-based architecture with a wireless communication system utilizing Wi-Fi and mobile networks to monitor train positions, with the transition expected to continue through 2034.