This series contains a variety of material including correspondence between officials of the WI&M, letters to other railroads and government agencies, reports, pamphlets, mimeographed material from several railroad associations, insurance and tax material, mail and express contracts and passenger and freight tariffs.

Folders numbered 1-313 retain their original numbers; folder 314 was originally numbered 350 but was renumbered for the sake of continuity. The material which was not in numbered folders was sorted by subject and folder numbers were assigned arbitrarily. Material in legal size folders is boxed separately from the material in letter size folders. Boxes 1-11 contain the letter size folders, boxes 12-14 the legal size. Folders 333 and 334 are in small file boxes numbered 15 and 16 respectively. It should be mentioned that some of the original folders are missing.

The numerical list, which also contains a brief description of the folder contents, is followed by a subject index which is based on the key to the filing system which accompanied the collection, although additional subjects were added for material not originally in the numbered folders. The original key to the filing system will be found in box 439.

In the Numerical List of Office Files, an asterisk preceding the folder number indicates that the material is in a legal size folder.