Many of these books are still in publication and can be found at your favorite 
Hobby Shops and book stores.
For those out of print here are a couple places to try: 1. Abe Books, 2. Amazon Books, and 3. Railpub used books and magazines.
Abe books and Amazon Books have search engines, just enter the title and Author of the book. Railpub has an online listing in PDF format. If you don't have Adobe Acrobat you can download it from the Railpub web site.
Alexander The June Bug Line Matthew Bumgarner 1992
ALL American Car & Foundry, Kaminski 1999
ALL The Magor Car Corporation, Kaminski 2000
ACL Atlantic Coast Line-The Diesel Years Calloway, Warren L. 1993
ACL Atlantic Coast Line Railroad: Steam Locomotives Ships and History Prince 1975
C&NW The Legacy of the Carolina & Northwestern railway Matthew Bumgarner 1997
Cape Fear Cape Fear & Yadkin Valley Railway Matt Bumgarner 2000
C&O C&O-Locomotive history and photos. Staufer None
C&O C&O Power Huddleston, Eugene L., Shuster, Philip & Staufer, Alvin F. 1965
C&O Chesapeake and Ohio Diesel Locomotives Shaver, Carl W. & David L. Gilliland 1994
CofGA Central of Georiga-Passenger car diagrams. SRHA
CofGA Central of Georgia Railway and Connecting Lines Prince, Richard E. 1976
CofGA Central of Georgia Railway Passenger Equipment Diagram Book Eichelberger 1995
CRR Clinchfield Country King, Steve 1988
ELEC Hill City Trolleys Cox, Harold E. 1977
ELEC Palmetto Traction: Electric Railways of South Carolina Fetters, Thomas 1978
ELEC The Streetcars of New Orleans Charlton, E. Harper & Hennick, Louis C. 1975
ELEC The Trolley Titans Carson, O.E. 1981
ETWNC Tweetsie Country Ferrell, Mallory Hope 1976
FEC Rails 'Neath the Palms Mann, Robert W. 1983
FEC Speedway To Sunshine Branson, Seth 1984
GA Georgia Railroad Album Beckum, & Langley 1985
GA Georgia Railroad and West Point Route Prince, Richard E. 1962
GA Ghost Trains & Depots of Georgia (1833-1933) Winn, Les R. 1995
GA History of the Georgia Railroad Hanson, Robert H. 1996
GA Safety-Courtesy-Service The History of the Georgia Railroad Hanson 1996
GM&O GM&O North Olmsted, Robert P. 1976
GM&O The Gulf, Mobile & Ohio Lemly, James H. & Richard D. Irwin 1953
IC Illinois Central Streamliners 1936-1946 Somers, Paul M. 1995
Lawndale Lawndale Railway and Industrial Company Bumgarner, & others 1999
IC Limiteds Along the Lakefront: The Illinois Central in Chicago Lind, Alan R. 1986
IC Main Line of Mid-America Corliss, Carlton J. 1950
IC Monarchs of Mid-America Randall. W. David & Lind, Alan R. 1973
INT The Interstate Railroad: History of an Appalachian Coal Road Wolfe, Ed 1994
L&N Louisville & Nashville Steam Locomotives Prince, Richard E. 1968
L&N Queen & Crescent Route Gardner, Edward F. 1976
L&N The Louisville and Nashville in the Appalachians Flanary, Oroszi, & Mckee 1990
MISS Delta Route Saillard, Louis R. 1981
MISS Natchez Route Price, David S. & Louis Saillard 1975
N&W N&W-Caboose photos, rosters and plans. N&W Histor. Society
N&W N&W - A-class history, drawings, photos and roster. Trans-Anglo
N&W Cabooses of the Norfolk and Western Bowers & Brewer 1994
N&W N&W: Giant of Steam Jeffries, Lewis Ingles 1980
N&W Norfolk & Western and Virginian Railways in Color Reid, H. 1994
N&W Norfolk & Western Steam Rosenberg, Ron & Archer, Eric H. 1973
N&W Norfolk and Western Coal Cars from 1881 to 1998 Dow, Andrew 1998
N&W Norfolk and Western in Color-Vol. 1 Nichols, Jim 1997
N&W Norfolk and Western Passenger Service: 1946-1971 Warden, William E. 1990
N&W Norfolk and Western Railway:First Generation Diesels Bowers & Withers 1990
N&W Norfolk and Western Railway:Pocahontas Coal Carrier Prince, Richard E. 1980
N&W Norfolk and Western Railway:Second Generation Diesels Bowers & Withers 1989
N&W Norfolk Southern Railroad-Old Dominion Line and Connections Prince 1972
N&W The A - Norfolk and Western's Mercedes of Steam King, Ed 1989
N&W The Norfolk and Western Handbook Wiley, Aubrey & Wallace, Conley 1980
N&W Tidewater Triangle Yanosey, Robert J. 1988
NC Rails to Weeds, Searching Out the Ghost Railroads Around Wilmington Kernan 1988
NPBL Virginia's Belt Line Railroad: The Norfolk & Portsmouth, 1898-1997 Moomaw 1998
P&N Piedmont and Northern: Swanson, Peter W. Jr. & Fetters, Thomas T. 1974
PULL Pullman Standard - Vol. 07-Southeast roads Randall, W. David 1989
PULL Pullman Standard - Vol. 11 Randall, W. David 1992
PULL Pullman Standard - Vol. 12 Illinois Central Randall, W. David 1992
PULL The Official Pullman Standard Library-Selected Heavyweight cars Randall, David w. 1995
RF&P One Hundred Fifty Years of History Along the Richmond Fredericksburg and Potomac.
RF&P Railroading on the Washington Division Conner, E. R. III 1986
RF&P Rails in Richmond McKenney,Carlton Norris 1986
RF&P Richmond Fredericksburg & Potomac- The Capital Cities Route Griffin, Jr., William E. 1996
RF&P R F & P Railroad-Linking North and South Kaplan, Bob & Melander, Deane 1990
RF&P The Richmond-Washington Line and Related Railroads Prince, Richard E. 1973
SAL SAL-History & photos of Virginia div. William E. Griffin
SAL All Lines North of Raleigh Griffin, Jr., William E. 1991
SAL Seaboard Air Line Color Guide to Freight and Passenger Equipment Faulk, Paul 1998
SAL Seaboard Air Line Railway Album Langley, Beckum, & Tidwell, C. Ronnie 1988
SAL Seaboard Air Line Railway: Steam Boats Locomotives and History Prince, Richard E. 1969
SAL Seaboard Air Line Railway: The Route of Courteous Service Griffin Jr., William E.
SAL Seaboard Motive Power Calloway, Warren L. & Withers, Paul K. 1988
SLSF Frisco Power-Locomotives and Trains of the SLSF RR 1903-1953 Collias, Joe G. 1984
SRR The Floods of July 1916 Matthew Bumgarner Softcover
SRR SRR-1943 Rulebook. Southern None
SRR SRR-Depot history and photos. Ralph Ward 0-9622999-3-6
SRR SRR-History and photos. Quadrant
SRR SRR-January 1, 1957 passenger car diagrams and roster. Another Man's Treasure None
SRR Classic Diesels of the South Lamb, J. Parker 1997
SRR Crossties Over Saluda Gilbert, John F. 1971
SRR Crossties Through Carolina, John & Grady Jefferys 1969
SRR Crossties to the Depot: Volume 1 Virginia Railroad Stations Gilbert, John F. 1982
SRR Diesels of the Southern Railway Withers & Calloway 1997
SRR Locomotive 4501 Morgan, David P. 1968
SRR Southern Motive Power Pictorial 1968-1982 Sink, Tom L. & Withers, Paul K. 1987
SRR Southern Ps-4 Class Pacific Locomotive Drawings Fitt, William C.(ed.) 1973
SRR Southern Railway Color Guide to Freight and Passenger Equipment Kinkaid, James 1996
SRR Southern Railway Diesel Locomotive Diagram Book 1995
SRR Southern Railway in Color Cheney, Fred D. & Sweetland, David R. 1993
SRR Southern Railway Panorama Kramer, Frederick A. 1978
SRR Southern Railway System :Steam Locomotives and Boats Prince, Richard E. 1970
SRR Southern Railway System Passenger Car Diagrams 1984
SRR Southern Railway System, Book of Operating Rules None 1943
SRR Southern Railway System:A Pictorial Album Nuckles, Douglas B. & Tillotson, Curt Jr. 1996
SRR Southern Railway Varnish Ward, Ralph 1986
SRR Southern Railway's Murphy Branch George, Michael 1996
SRR Southern Railway's Spencer Shops 1896-1996 Galloway, Duane & Wrinn, Jim 1996
SRR Southern Steam Power Lowe, Shelby F. & Ranks, Harold E. 1966
SRR Southern Steam Specials (Revised) Eagleson, Mike & Ziel, Ron 1975
SRR Southern Steam Specials Eagleson, Mike & Ziel, Ron 1970
SRR The Southern Railway Depots-Vol. 1 North Carolina Ward, Ralph 1991
SRR The Southern Railway Depots-Vol. 2 Ward, Ralph 1994
SRR The Southern Railway Durham, Robert K. 1966
SRR The Southern Railway Handbook Wiley, Aubrey & Wallace, Conley 1983
SRR The Southern Railway System Webb, William 1986
SRR The Southern Railway: Road of the Innovators Davis, Burke 1985
STEAM The Georgian Locomotive Bryant, H. Stafford 1962
STEAM Trains Album of Photographs, No.5 None 1944
STEAM Trains Trestles & Tunnels: Railroads of the Southern Appalachians Harshaw, Lou 1977
STEAM Union Station Highsmith, Carol M. & Landphair, Ted 1988
TENN Ghost Railroads of Tennessee Sulzer, Elmer G. 1975
TENN History of the Lookout Mountain Incline Rwy
VGN Virginian-Color photographs. TLC Publishing
VGN The Virginian Era Lewis, Lloyd D. 1992
VGN The Virginian Railway Handbook Wiley, Aubrey & Wallace, Conley 1985
VGN The Virginian Railway Reid, H. 1973
VGN Virginian Railway Locomotives Lloyd D. Lewis 1993
W&OD Washington & Old Dominion Railroad Williams, Ames W. 1977
S.A. McCall