The railroad's results fell short of expectations.Union Pacific (UNP -5.21%) results fell short of expectations as the railroad works to reduce costs in a tough operating environment. Investors took the news hard, sending UNP shares down 5% as of 10:30 a.m. ET.Operational improvements in a tough environmentUnion Pacific is one of two primary railroads serving the western half of the United States, with more than 32,000 miles of track and access to key Pacific ports. But demand for shipping services has been ...