5.25-inch floppy disks expected to help run San Francisco trains until 2030

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The San Francisco Municipal Transportation Agency (SFMTA), which runs the city's Muni Metro light rail, claims to be the first US agency to adopt floppy disks. But today, the SFMTA is eager to abandon its reliance on 5¼-inch floppy disks—just give it about six more years and a few hundred more million dollars.

Members of the SFMTA recently spoke with the ABC7 Bay Area News and detailed the agency's use of three 5¼-inch floppy disks every morning. The floppies have been part of Muni Metro's Automatic Train Control System (ATCS) since its installation in the Market Street subway stop in 1998. The ATCS has multiple components, "including computers onboard the trains that are tied into propulsion and brake systems, central and local servers, and communications infrastructure, like loop cable signal wires," Michael Roccaforte, an SFMTA spokesperson, told Ars Technica.

The floppy disks are for loading the software running the central servers, Roccaforte said: