Hillcrest Complex,[2] the Toronto Transit Commission's largest facility, is responsible for most of the maintenance work on the system's surface vehicles, including heavy overhauls, repairs, and repainting.

The site is also home to the TTC's Transit Control Centre, but the operational headquarters of the organization remains at the McBrien Building, at 1900 Yonge Street.

[3] In 1922, the TTC purchased the Hillcrest Race Track to use its land for the new shop complex to replace smaller facilities inherited from the Toronto Railway Company.

The TTC opened Hillcrest Complex on March 13, 1924, replacing the TRC's carshops, motor shops and stores building located at or near at Front and Frederick Streets.

After its opening in 1924, the Hillcrest Complex received railway shipments of coal, gravel and sand for use throughout the system.

The shops occupy a space of 250,000 square feet (23,000 m2) and is divided into sections for trades such as upholstery, blacksmith and carpentry.

So, when ALRV streetcars with a length of 23 metres (75 ft) were introduced, an addition was built on the easternmost tracks with direct access from outdoors to allow the ALRV cars to drive through the old building crossing the transfer table into a longer wing on the northeast side of the building where they are maintained.

[7] The Harvey Shops can rebuild buses and older streetcars by stripping the vehicles to their frames, assessing corrosion and repairing or replacing parts as needed.

Opened in the 1980s, the building was designed with security in mind to handle fare media such cash, tickets, tokens, passes and transfers.

The TTC's Transit Control Centre is located in the three storey Gunn Building at the northeastern corner of the Hillcrest Complex.

The facility has 3,800 m2 (41,000 sq ft) of space containing mechanical, electrical, and computer equipment, offices and a training area.

In addition to subway/SRT train control, the facility monitors traction power, security, fire safety, communications, ventilation and mechanical systems.

Outside the building, there would be 4,000 m2 (43,000 sq ft) of space for the pre-assembly of special track work (switches, crossings and connecting curves) and the storage of equipment and materials.

Changes considered included:[7][25][26] In 2020, the TTC proposed setting up a carhouse at the Hillcrest Complex, to store and service 25 streetcars; the project had a then-estimated cost of $100 million.