Starting at the Bingham Loop on Victoria Park Avenue, the 503 runs southwest on Kingston Road then turns west along Queen Street. At the Queen Street Viaduct bridging the Don River, it then turns southwest along King Street, enters the King Street Transit Priority Corridor and continues to Spadina Avenue, where it turns on the Charlotte Loop. The 503 Kingston Rd runs weekdays excluding evenings. Evening, weekend and holiday service is provided by the 22A Coxwell bus route replacing streetcar service along Kingston Road. The section to the west of Queen and Coxwell is served by the 501 Queen and 504 King streetcars. Both of these routes provide all-day service.
History
Two streetcar routes, 503 Kingston Rd and 502 Downtowner, serve Kingston Road. Route 502 Downtowner was originally named "Kingston Rd" while 503 Kingston Rd was originally named "Kingston Rd Tripper". The Kingston Rd route ran from the McCaul Loop to the Birchmount Loop until 1954 when it was cut back to the Bingham Loop. By 1968, the rush-hour route Kingston Rd Tripper was appearing in TTC Ride Guides. "Tripper" here means a rush-hour variant of a base route which in this case was the Kingston Rd route. In 1973, the Kingston Rd route was renamed to "Downtowner" with a route extension to Bathurst station that was revoked in 1984. Also in 1973, with the renaming of "Kingston Rd" to "Downtowner", the Kingston Rd Tripper became simply "Kingston Rd" and ultimately the 503 Kingston Rd. From July 31, 2017, until February 16, 2018, the 503 Kingston Rd route was temporarily operated using buses due to a shortage of streetcars resulting from the late delivery of the new BombardierFlexity Outlook streetcars. On February 20, 2018, the 502 Downtowner and 503 Kingston Rd routes reversed roles. Prior to that date, route 502 provided base workday service supplemented by route 503 in the rush hours. Since that date, route 503 provides base service while route 502 provides rush-hour-only service. These changes were to support the King Street Pilot Project which resulted in increased ridership along downtown King Street. However, effective September 2, 2018, these changes were reversed. On January 7, 2019, the 503 route returned to shuttle bus operation to accommodate construction along Wellington Street. Effective September 3, 2019, the 502 Downtowner service was suspended and replaced with the 503 Kingston Rd service to accommodate some construction projects. Route 503 service was upgraded to operating weekdays excluding evenings instead of just during rush hours. The construction projects ended in November 2019; however, the consolidation of Kingston Road service into 503 Kingston Rd remained in effect. In March 2020, the COVID-19 pandemic resulted in a loss of ridership on the TTC. As a result, on March 24 the TTC shortened the 503 Kingston Rd route to run only along Kingston Road between Bingham Loop and Woodbine Loop. Then, effective May 11, the 22A Coxwell bus replaced the remainder of the 503 route full-time On June 22, 2020, streetcar service returned to the route, running from Bingham Loop to Spadina Avenue. Service was provided by the low-floor, accessible Flexity Outlook streetcars. The return of streetcars along 503 Kingston Rd coincided with the withdrawal of streetcars on 506 Carlton due to construction projects.
