The Arizona Department of Transportation has been involved with railroad planning since 1976, with its first State Rail Plan Update issued in 1978. The most recent report, the 2000 Arizona State Rail Plan Update was an important starting point for this Inventory and Assessment in that the seven-year-old study provides the description and inventory of Arizona railroads as they existed at that time. There have been a number of important changes over the intervening years, and these are reflected in this 2007 Inventory and Assessment. In addition to the 2000 State Rail Plan Update, RLBA made use of the 2003 Maricopa Association of Governments (MAG) High-Capacity Transit Study and the 1998 Arizona High Speed Rail Feasibility Study. The information contained in this report was gathered from a number of sources, including the railroads themselves, ADOT, the Arizona Corporation Commission, MAG and numerous Arizona officials. A listing of persons who contributed to this Railroad Inventory and Assessment is provided under “Acknowledgements” inside the front cover. Information in this report also was obtained from the Association of American Railroads and from RLBA’s extensive data banks.