The streetcar route along St. Clair Avenue was created by the Toronto Civic Railways in 1911 in a successful attempt to promote development in a newly annexed section of the city. Originally, the route ran in a dedicated right-of-way. The route was transferred to the Toronto Transportation Commission upon its creation in 1921, which removed the dedicated right of way in 1928. It is the northernmost streetcar route still in operation, and was the first to make an underground connection with the subway at St. Clair West Station. It formerly continued beyond St. Clair Station and up Mount Pleasant Road to Eglinton Avenue, but this portion was later made a separate route that was subsequently converted to bus operation in the 1970s.
When first built, the St. Clair streetcar operated in a dedicated right-of-way, similar to the modern 510 Spadina route. A dedicated right-of-way is a lane generally in the centre of the street, reserved for transit vehicles. However, it was removed between 1928 and 1935 and replaced with paved trackage open to mixed traffic. The TTC later came to regret this decision, and in 2005 it began rebuilding a dedicated streetcar right-of-way.
The TTC is now running a pilot project of time-based transfers on portions of the 512 St. Clair, under which passengers who take a transfer (see Toronto Transit Commission fares) may disembark and then board another streetcar from the same route, even one going in the opposite direction, as long as they do so within a certain amount of time after their original boarding. This means that one can stop part-way through a journey and then continue, or even make a round trip, without paying multiple fares.
The line is operated with Toronto’s non-articulated CLRV streetcars.
Roncesvalles Carhouse serves the St. Clair streetcar route. When a 512 St. Clair streetcar begins service, it travels from the yard at Roncesvalles and the Queensway, along King Street, then on Bathurst Street, which connects to St. Clair Avenue. When a 512 streetcar finishes service, the roll sign indicates "512 RONCESVALLES", and the vehicle travels on Vaughan Road to Bathurst and King Streets, ending in Roncesvalles Yard, with some ending at Bathurst Street's Hillcrest Yard.
Following the success of the new 510 Spadina route along dedicated right-of-ways on Spadina and Queen's Quay and on portions on several streetcar routes, the TTC decided to upgrade the St. Clair streetcar to a dedicated right-of-way. The tracks along the route needed replacement, and the TTC estimated that building a dedicated right-of-way would cost only $7 million more than simply replacing the tracks. Furthermore, St. Clair Avenue is one of the few streets in Toronto wide enough to accommodate a dedicated right-of-way without significantly reducing the width of traffic lanes.
Two major plans have been proposed and examined in the past. The first plan would see Route 512 extended west along St. Clair Avenue West to Runnymede Road, and south underneath the Canadian Pacific Railway Galt Subdivision line to a bus loop at Runnymede Road and Dundas Street West, replacing a portion of route 71 Runnymede. Streetcar tracks would then be extended southeast along Dundas Street West to Dundas West Station where the 504 King and 505 Dundas streetcar routes currently terminate. The tracks on Dundas would be served by a new route replacing the current 40 Junction bus route. While this scheme may not be warranted by potential ridership, it would cut down the amount of deadhead (not-in-service) time required by St. Clair streetcars to get to St. Clair Avenue.
The other plan comes as part of Transit City, the Light Rail expansion proposal. It would see route 512 extended west on St. Clair all the way to Jane Street, replacing portions of routes 71 Runnymede and 79 Scarlett Road, where it would connect with the planned Jane Street LRT.
The St. Clair west right of way consists of 26 stops (east to west). Full Streetcar service resumed (St. Clair Station to Gunns Loop) on June 30, 2010. Streetcar service resumed to Earlscourt Loop (Lansdowne Ave.) December 20, 2009, with a pre-opening event on the 19th utilizing the TTC's two remaining PCC streetcars. Prior to that portion of the line being reopened streetcars only serviced stops between St. Clair and St. Clair West Stations.
The Torontoist reports that, even during rush hour, it takes 29 minutes to travel the entire route, from Yonge Street to Gunns Road.
Unlike the 512 route, the 312 Blue Night buses stop at the curb (sidewalk), not the streetcar islands. Recently, the TTC placed several signs along the route to indicate this, likely due to passenger confusion over new, "far-side" streetcar stops while the curb bus stops remain "near-side" (stopping before crossing the intersection).
Transfer points on St. Clair and Jane, 312 St. Clair Blue Night bus:St. Clair Station - 320 Yonge Blue Night bus
Bathurst Street - 307 Bathurst Blue Night bus
Oakwood Avenue - 363 Ossington Blue Night bus
Dufferin Street - 329 Dufferin Blue Night bus
Keele Street - 341 Keele Blue Night bus
Jane Street - 335 Jane Blue Night bus
Dundas West Station - 300 Bloor-Danforth Blue Night bus