For those who wish to find reading material about lithographs as used in locomotive advertising and also of a more general nature, the following are suggested.
White, John H., American Locomotives, John Hopkins University Press, 1968, 1997. The pre-eminent book on early American locomotives and illustrated with several reproductions of lithographs.
White, John H., Locomotives on Stone, from The Smithsonian Journal of History, vol.1, 1966. A small monograph profusely illustrated with lithographs.
Alexander, Edwin P., Iron Horses, W. W. Norton & Co., 1941. This book has the largest number of reproduced lithographs.
Alexander, Edwin P., Civil War Railroads and Models, Clarkson Potter, 1977. This book has several reproduced lithographs not rshown in Iron Horses.
Last, J. T., The Color Explosion, Hillcrest, 2005. this elaborate book has several locomotive lithograph illustrations along with copius information regarding American litographers.