TYENDINAGA, Ontario — A dilapidated snow plow, three tents and some barrels sit beside the snowy tracks of the Canadian National Railway in Tyendinaga, Ontario, a protest in support of Indigenous leaders trying to stop the construction of a gas pipeline thousands of miles away, in British Columbia.

The blockade, set up by the Mohawks of Tyendinaga, may not look imposing. But the barricade, and similar ones erected at transport points across the country, has disrupted travel for Canadians since last week — and drawn attention to the pipeline dispute.

Tens of thousands of travelers have had to scramble after rail service was halted between Toronto and the cities of Montreal and Ottawa. Hundreds of freight trains have been stalled, and ports in eastern Canada have been isolated from the rest of Canada and the United States. Factories have braced for closing because of delivery interruptions.

On Wednesday, Prime Minister Justin Trudeau weighed in for the first time, calling on all sides “to resolve this as quickly as possible.”