Some possible titles are:
Civil War Railroads: A Pictorial Story of the War between the States, 1861-1865, by George B. Abdill, published by Indiana University Press
The Northern Railroads in the Civil War, 1861-1865, by Thomas Weber, published by Indiana University Press
Thomas Weber also wrote
Victory Rode the Rails: The Strategic Place of the Railroads in the Civil War. The paperback version of this was published by University of Nebraska Press; it is out of print, but you can find it on any of several used book on-line listing services.
Brian Norden