Rail operations are ubiquitous throughout the United States. They operate in every state in the US except Hawaii, across a network that exceeds 140,000 miles (BTS, 2003). The 559 freight railroads move over 1.7 trillion ton miles of freight (AAR, 2007). The 22 commuter railroads alone move 1.4 million people daily (APTA, 2007) and the Amtrak intercity passenger service adds over 75,000 more (BTS, 2008).