A most useful tool for understanding the railroad business at the beginning of the 20th century, The Official Railway Equipment Register has been essential in decoding and understanding many of the firms that cancelled stamps in the 2ct documentary calendar featured on this site. The document is available online and can be downloaded, and its age means that the content is out of copyright.
Every generation of US government issued revenue stamps has its own tools for understanding the businesses that were the major users of the tax stamps. By 1898, the railroad business in the United States was gigantic, and a major source for growth and facilitator of the economic and physical expansion of the United States. The Official Railway Equipment Register and Poor's Manual are essential items for the 1898 documentary stamp collector.