This CD book contains George Melvin's in-depth series on the history of ALCO's S-1 and DL109 locomotives and the roads that used them. Designed to be an invaluable tool for both modelers and historians, the CD presents both series in PDF format (Adobe® Reader® 5.0 or later required). The text is fully searchable, and all 256 high-resolution photos (75 in color) can be zoomed in on for close examination of every detail...something not possible with a printed version. Because the images are 300 dpi rather than the more common 96 dpi, readers can get an extremely close look at fine details. Pages can be printed for personal use. The 96-page S-1 series was first published in the October 2002 to August 2004 issues of Model Railroading magazine, and the 8-page DL109 series was in the June and July 2005 issues.