Located at the northwest corner of the Queensway and Roncesvalles Avenue in Toronto, Ontario, west of its downtown core, it is the oldest of the TTC's three active carhouses.

When the City took over streetcar operations in 1921, its new transit agency, the Toronto Transportation Commission, determined the existing facilities should be torn down and replaced.

[6] This arrangement continued until February 9, 1935 when the Port Credit radial (then running west from the Long Branch Loop) was permanently replaced by bus service.

[7] By 2013, 26,000 square feet (2,400 m2) of new maintenance capabilities were added to the carhouse to handle the new low floor Flexity streetcars introduced in 2014.

[8][9][10][11] As an addition to the Roncesvalles structure, the TTC added a new one-track service bay capable of providing some maintenance for the new low-floor streetcar vehicles.

In January 2019, Roncesvalles Carhouse partially reopened to service some of the Flexity Outlook streetcars used on routes 501 Queen, 504 King and 512 St.

To prevent further incidents, the TTC has since required drivers to go around the S-curve at 5 km/h (3.1 mph) with the pantograph raised and the trolley pole lowered.