Letters were adopted for identification of the bus routes after conversion, originally A-B-C. These bus routes originally duplicated the streetcar routes, with a few exceptions or renamings. The Wingra Park line was renamed Westmoreland, after being combined with the Wingra bus line. And the Winnebago line was renamed the North St. line. Also the West Main line was dropped, and Nakoma became a bus line, acquired from Madison Realty Co. And there were some changes, in which lines were through routed with which other lines.
Additional letters were assigned as new bus routes were created. Madison grew considerably after the elimination of streetcars, and the present bus system bears little resemblance to the streetcar system.
Route Route Letter Name A Fair Oaks-Westmoreland B Nakoma-Johnson C North St.-South Madison/Park St. D Capitol Park-Hudson Park (rush hour only) E Winnebago-Allen St. (rush hour only) F Park St./Johnson (rush hour only) G Sherman-Shorewood/Highland Park H Lake Edge-Truax K West CrosstownThese routes were operated under the private ownership of the Madison Bus Co. Besides the three original routes A-B-C, only route G remained intact into the Madison Metro era. Although the basic routes were extended, and branches were created. Route G served areas along Lake Mendota, Madison's north shore.
In more recent years, Madison Metro replaced the letters with route numbers, and reconfigured many routes. No attempt is made to compare historic routes with the present routes.