WATFORD, Ont. -- Ontario NDP Leader Andrea Horwath had an unexpected campaign stop during her swing through southwestern Ontario on Wednesday -- a campaign bus breakdown.

Horwath's bus, dubbed the "Proletariat Chariot" by media riding on it for the campaign, experienced mechanical problems on Highway 402 near Watford, Ont.

The bus pulled over safely after a burning smell started to enter the cabin.

A faulty fanbelt was believed to be the problem.

"I'm going to check the engine," Horwath said, walking off the bus to assess the situation.

"Time for a .FanbeltChange4TheBetter," she tweeted a short time later.

Horwath's communications team said the breakdown was proof their campaign is "hot."