OMAHA, Neb. (AP) — Another major railroad has gone to court to determine whether it has the authority to require all its employees to get vaccinated against the coronavirus. BNSF railroad filed a lawsuit Sunday against its major unions over its mandate. It joins Norfolk Southern and Union Pacific, which both filed similar lawsuits against the unions last month. The unions, which have filed some of their own lawsuits in response, argue that the railroads should have negotiated with them before imposing their mandates. The railroads that have imposed vaccine mandates say they are complying with President Joe Biden’s executive order requiring all federal contractors to have their employees vaccinated.