Some 700 workers at Bombardier\'s Thunder Bay, Ontario factory have gone on strike after negotiations for a new contract failed, their union has said. Workers at the factory where bi-level rail cars, street cars and subway cars are built have been without a contract since the end of May, the Canadian Auto Workers union (CAW) said. \"Negotiations fell apart over demands for cuts to the pension plan, particularly for new workers,\" the CAW said in a statement. The strike began Tuesday after the Toronto Stock Exchange closed up 3.75 percent after shedding 4 percentage points Monday. Shares for Bombardier finished the day up 6 percent.