So goodbye, old fiend. Time to step down to open that back door in the sky. Muni's tribute:

Public transportation on Third Street began as a horsecar line and converted to electric streetcar service around the turn of the century. The 15-Third bus line began service on June 23, 1940, when buses replaced the 15 streetcar line.

On a regular weekday, buses on the 15-Third line traveled approximately 3,000 miles, taking passengers from City College to Fisherman’s Wharf and back. After 67 years of service to the public, the 15-Third retires April 7, 2007.