Two Teamsters-affiliated unions announced opposition to Union Pacific and Norfolk Southern’s proposed $85 billion merger, saying months of talks left them unconvinced and raising fresh safety and cost concerns after earlier reports showed union unease.Union Pacific says the deal would speed deliveries and help rail compete with trucking, but supporters and critics — including BNSF, the American Chemistry Council, hundreds of shippers, more than 99 percent of shareholders and the STB review process — will now press competing cases as regulators weigh public interest and competition.