Tunnels: About

There are currently about fifteen miles of underground track in the SFMTA subway, and another three planned for the future Central Subway.  Every fifty feet for most of it, there’s a vaportight fluorescent fixture with a 32W T8 lamp installed for egress lighting in the event that an evacuation is necessary, and also for nightly maintenance checks of the electrified cable and tracks.  It’s not a terrible solution for the era in which it was installed, but multiplied by thousands of fixtures, it represents a considerable burden in terms energy consumption and maintenance.  The entire subway tunnel system is planned for a phased replacement with LED fixtures.