Two cars left the tracks at around 7:30 a.m. local time (1230 GMT) and the RCMP said there were no leaks detected, or injuries or fire as a result of the accident.
Emerson, located near the US border, is 110 kilometres (68 miles) south of Winnipeg, Canada's rail network hub.
The derailment comes at a time of increased regulatory scrutiny on the railroads, as Canada and the United States ramp up efforts to increase rail car safety after a series of fiery accidents involving trains carrying crude oil.
An RCMP spokeswoman said it was unclear when residents would be able to return to their homes, or what had caused the derailment.