Bombardier Transportation performs train maintenance at the facility on behalf of Metrolinx, the owner of GO Transit.

[4] By April 2021, GO Transit had installed 2.6 kilometres (1.6 mi) of guard rails and warning lines along the roof edges of the seven buildings at the depot.

These were to protect workers who maintain heating, ventilation, and air conditioning (HVAC) units and other electrical and mechanical equipment mounted on the roofs.

HVAC units run 24/7 and keep the air in buildings clean and safe for workers such as for those working near locomotive engines.

[5] The Willowbrook Rail Maintenance Facility is located on a 18,600 m2 (200,000 sq ft)[6] site and features:[4] As of 2021, the depot works around the clock to service, clean and fuel 28 trains each day.