During the winter, bus companies take a number of precautions to ensure the more than 20,000 school bus riders in Sudbury aren't left out in the cold.

But operators say a new fleet of buses they're rolling out may not be built for northern Ontario winters — a theory that was tested Wednesday as Sudbury logged a record-breaking temperature of -36C and buses were cancelled.

At Leuschen Transportation's school bus yard in Sudbury, starting the engine isn't an issue for the new fleet of buses at the company: keeping them warm is.

How low did it go?

At 7 a.m. on Wednesday, Sudbury was sitting at -36C — a degree colder that the previous record for Jan. 23, set in 1976. Much of the northeast is also under a windchill warning.

A meterologist with Environment Canada said relief from the extreme cold is still a few days away.

The windchill warning issued by Environment Canada for Wednesday said it could feel as cold as -50C in Sudbury, North Bay,  the Temiskaming area, Timmins, Kapukasing, Hearst and the James Bay Coast.

As part of a new emissions framework put in place in 2009, the company has been required to buy more energy efficient versions of the big yellow bus.

That creates a problem, according to Matthew Hnatuik, one of the shop foremen.

"The engines are running cooler, so we do have a heat issue with the bus that we are trying to remedy," he said.

"It's a battle we're fighting constantly. We have engines that are losing power because of the lack of heat generated and the issue of people and our passengers being cold."

Riders need to dress warmly

A spokesperson with the Sudbury Student Services Consortium said she has been hearing about the cold temperatures on buses from parents.

"When I talk to parents I always remind them that, even if they do have high school students, they should be dressing up warmly," Renee Boucher said.

Leuschen Transportation said it has 80 to 100 of the new buses, which are part of an overall fleet of more than 250 vehicles. Upgrading the heater system in the vehicles would cost about $4,000 per bus.

In the meantime, if one of Leuschen Transportation’s buses breaks down on one of the more than 200 bus routes it operates across the city, the company has an immediate-response plan.

"We send out one of our mechanics [who] bundle up very well," Hnatuik said.

"We send them out with a bus, a battery charger, a couple of batteries, every possible tool we think they could use out there. And bring the drivers a bus and send the mechanics out to get the buses going at the drivers’ locations."

Hnatuik added school buses are also well maintained. He said when buses are in the lot they are plugged into block heaters overnight. Bus drivers are also encouraged to keep the buses fueled at more than half a tank throughout the winter.