Members of the SMART-TD union with train and yardmaster jobs will keep their career jobs if the merger of Union Pacific and Norfolk Southern is approved, under an major railroad agreement that was announced Monday. The union called it a “groundbreaking agreement ensuring job security for thousands of railroad workers.”Union Pacific CEO Jim Vena likewise sounded enthused. SMART-TD (Sheet Metal, Air, Rail, and Transportation Workers — Transportation Division) represents the locomotive conductors at Bailey Yard. SMART-TD claims to be the largest rail union in North America, representing more than 100,000 workers, spokesman Dan Banks said. If the merger goes through, Union Pacific will become a transcontinental railroad, serving 43 states and linking about 100 ports.