(CNN) -- Power returned to downtown Toronto on Monday night after a fire in a transformer knocked out service to more than 200,000 customers and brought much of the city to a standstill for about four hours, officials said.
The disruption in service started at 4:42 p.m. on a day when the city was under an extreme heat alert with a high of 93 F (34 C).
Electricity was restored at 8:30 p.m. ET, said Hydro One, the city's electrical power company.
A Hydro One spokesman said there were no injuries or health issues reported due to the incident.
The outage stalled the city's electric-powered trains, forcing the evacuation of as many as 400 passengers.
"Four hundred people from three trains had to be evacuated," said Jessica Martin, spokeswoman for the Toronto Transit
Commission."All the passengers were removed safely from the trains."
One of the downtown buildings that lost power in the outage, the Royal York Hotel, was the setting for a state dinner attended by Queen Elizabeth II and the Duke of Edinburgh.
The dinner, hosted by Prime Minister Stephen Harper, proceeded despite the outage, according to CNN affiliate, CBC.