Canadian National Railways conductors, trainpersons and yardpersons have threatened to launch a strike in three weeks after six months of negotiations.

The Teamsters Canada Rail Conference disclosed Monday that its 3,000 members voted 99.2 per cent last month in favour of a strike.

A strike could begin at 12:01 a.m. on Nov. 19, after the union provides at least 72 hours' notice.

The union is trying to put pressure on the Montreal-based railway ahead of a resumption of negotiations with the help of federal mediators on Nov. 12.

The workers, who are mostly located in major urban centres across Canada, have been without a contract since July 23.

CN Rail lowered its forecasts last week by pointing to a deterioration in North American rail demand and a further slowdown in the economy.

"CN remains committed to working with the TCRC and is optimistic that an agreement will be reached," said a CN Rail spokesman.