MILWAUKEE — A collision between a train and a Union Pacific vehicle left four people injured Monday morning. Union Pacific confirmed to WTMJ that it happened around 9:30 a.m. on May 11 at the Butler rail yard near 119th St. and Hampton Ave. Four employees were taken to the hospital. Officials did not have details on the condition of those injured or the cause of the crash. The post Train collision at Union Pacific rail yard in Milwaukee appeared…