A rail strike in Canada is continuing to cause production disruption and transport problems for local carmakers, notably Ford.

Ford Motor Co. of Canada sent about 3,700 workers at three Ontario plants home on Tuesday after some union members supported a strike at Canada’s biggest railway by declining to unload rail shipments, spokeswoman Lauren More told the Reuters news agency.

More said the move by the Canadian Auto Workers union (CAW) members led to a parts shortage at the plants.

Reuters noted that the CAW also represents 5,000 striking Canadian National Railways workers, who account for nearly a quarter of CN Rail’s 23,000 employees. The rail strike started last Friday after contract talks failed over wage issues.

“We did have a parts shortage at the assembly plants due to the fact that some Ford CAW members are refusing to handle inbound rail shipments that feed the line,” More told Reuters.

Ford said 1,200 workers on the day shift at its St. Thomas, Ontario, assembly plant were sent home – for a second consecutive day – and 2,500 employees at its two Oakville, Ontario, plants, one of which makes trucks, were also told to go home.

According to Reuters, More said operations at Ford’s Windsor, Ontario, plant were running on schedule and the afternoon shift at the St. Thomas and Oakville assembly plants were slated to start on time – the truck plant is a single shift facility.

More said Ford, which moves about 2,500 finished vehicles a day, about 80% of that by rail, was not shipping out by rail either and was storing vehicles on site.

CN spokesman Mark Hallman told Reuters the railway was operating at “near normal” levels despite the strike.

“This issue at Ford is not an issue caused by CN service but by Ford CAW employees,” he said. “We remain, and have been, ready, willing and able to service all of our customers.”

A General Motors of Canada spokeswoman told Reuters the carmaker, which ships about 20% of its goods by truck and the rest by rail, has been making alternative arrangements for incoming parts shipments and outgoing shipments of finished vehicles.

“So far, we are able to get our production out and we’re probably getting close to being in a position where we’re going to have to park vehicles,” Pam McLaughlin told the news agency.

McLaughlin said parts coming into its plants were not unloaded by GM’s CAW-represented workers but outsourced to a group whose workers are represented by the Teamsters union.

DaimlerChrysler Canada told Reuters it had seen no manufacturing disruptions either inside or outside Canada.

Reuters said the firm relies on CN to ship engine parts from a plant in Mexico to its Brampton, Ontario, facility and frames from supplier Magna International to Chrysler‘s Dodge Durango manufacturing site in Newark, Delaware.

“Canadian National Rail has been able to maintain 100% of the pre-strike service,” DaimlerChrysler spokesman Dave Elshoff told Reuters.