Metrolinx is set to host the largest joint emergency exercise ever held at Union Station this weekend.

The exercise, which will involve Toronto police, Toronto Fire Services, Toronto Paramedic Services and the city, will begin late in the evening on Saturday November 2 and will last into Sunday morning.

The simulation has taken months of planning and will involve 150 actors, professional makeup artists, and fake smoke around the platforms.

“Safety is critical to everything we do at Metrolinx, and it is important to regularly test our emergency preparedness to ensure our staff and first responders are ready in the event of any type of critical incident at Union Station,” Metrolinx vice-president George Bell said in a statement.

According to the transit agency, all GO Transit bus and train, UP Express, VIA Rail and TTC services will operate as usual.

However during the simulation, the public may see volunteers pretending to be seriously injured, first responders acting out response protocols, and many emergency vehicles in the area.

Metrolinx is advising people not to call 911 to ask questions about what is happening at the station.

“In the event of an actual wide-scale emergency, the exercise will be cancelled, and first responders redirected,” the agency said in its statement.

Some sidewalk closures will be in effect around the station and staff will be onsite to direct customers, Metrolinx said.

The exercise was timed so as to cause the least disruption to transit, the agency said. Those who may be upset by the emergency activity are being advised to avoid the station during the simulation.