Tractors from Quebec farms rumbled back into Montreal on Monday morning to demand the federal government do something about the propane shortage caused by the CN Rail strike.

Last Friday, a convoy of tractors rolled up to CN's head office in downtown Montreal, where farmers declared that their livelihood is being threatened by the propane shortage.

Their destination this time was Prime Minister Justin Trudeau's constituency office in Montreal's north end. Farmers dumped bags of corn on the steps outside.

There has been increasing pressure on the federal government to deal with the strike by 3,200 unionized CN workers, which is now in its seventh day.

The government has so far said it hopes the union and CN can agree to a new contract through negotiation, a position that federal Agriculture Minister Marie-Claude Bibeau repeated again Monday.

A lobby group representing Quebec's agriculture industry said it doesn't want to interfere in the labour dispute, but did call on Trudeau to ensure that CN is doing what it can to protect the livelihoods of farmers.

Farmers use propane to heat hog barns and henhouses, as well as to dry grain before storage. The vast majority of Quebec's propane supply is imported by rail from Ontario.

Farmers rally in Montreal to protest a propane shortage caused by the CN Rail strike. (Ivanoh Demers/Radio-Canada)

Marcel Groleau, president of Quebec's farmers' union (UPA), said they're not asking for special legislation to force the CN employees back to work.

Instead, they want Trudeau and his government to "put pressure on CN" to prioritize the transportation of propane on the few trains the company is still operating.

"We're on the alert — it's an intolerable situation," Groleau told Radio-Canada.

A 'stressful' situation for everyone, farmer says

The UPA rallied dozens of farmers Monday morning at the Claude-Robillard sports complex in Ahuntsic-Cartierville, near Trudeau's constituency office.

Many came by bus, but another 30 came on tractors from Montreal's South Shore, slowing morning traffic as they made their way over the Jacques-Cartier Bridge.

Tractors clog a street near Prime Minister Justin Trudeau's constituency office. (Ivanoh Demers/Radio-Canada)

Dominique Leroux, a grain farmer from Montérégie West, said he's out of propane and that's thrown off his whole farming operation.

"I haven't touched my field yet," said Leroux, who is also a local representative of the Grain Farmers Association of Quebec.

"Everything is still in the field. I'm also a grain elevator owner, so what that means is I dry corn for other farmers and they have to leave their crops in the field because I can't dry their crops. That's really stressful for them, for me, for our family, for everybody."

Leroux said if the crops are lost, the impact could be widespread. Less corn would mean less feed for animals and less material for ethanol production and starch production — which have uses beyond food, such as in pharmaceutical manufacturing.