Starting at the Bingham Loop on Victoria Park Avenue, the 503 runs southwest on Kingston Road then turns west along Queen Street. At the bridge over the Don River, it then turns southwest going along King Street and continues west to Church Street. It then goes south again to Wellington Street where it continues west to York Street. It then turns north and returns east along King Street, Queen Street and Kingston Road.
^James Bow (2013-08-24). "Remembering Birchmount Loop". Transit Toronto. Archived from the original on 2013-09-21. Retrieved 2014-02-18. The easternmost streetcar loop in the TTC's history is Birchmount Loop, located at the Kingston Road / Birchmount Avenue intersection inside the old City of Scarborough.