8 ½ x 14 sheets printed on 39 pages. Reprinted from the original document that was issued by the C&O's Advisory Mechanical Committee. This reprint includes 37 pages of mechanical diagrams and data, shows the C&O's Locomotive Cranes in service as of its last update in 1964, but original drawings date back to 1926. (The original packet was assembled prior to 1957 and has several units that are scratched out suggesting they were in service in 1957, but not in 1964....important information to Modelers who model a certain era.) Mechanical Diagrams were used by most American railroads to document their locomotives and rolling stock, as did the C&O. These drawings, generally called "mechanical diagrams", were intended for use in supplying members of the railroad's mechanical department with a ready reference about the equipment concerned. They included a dimensional drawing, and listing of capacity, weights, clearances, and appliances, parts, types of brakes, builder, and date built, etc. These diagrams were assembled into books, which were supplied to mechanical personnel at each terminal and principal location on the railway so that they would have immediate data on any type of the company's equipment when it was in their territory or needed maintenance enroute. Modelers, be sure to notice which cranes have Arch Bar trucks, and which ones do not!