Pennsylvania Railroad 4-4-4-4 T1 Locomotive | Old Machine Press
English: Baltimore and Ohio Railroad duplex locomotive, class N-1 #5600 George H. Emerson, at the 1939 New York World's Fair. 17 June 1939. Gottscho-Schleisner Inc., photographer. 6 Baltimore and Ohio Duplex detail Stock Photo - Alamy
Duplex locomotive - Wikipedia
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Duplex Drive Locomotives.
Pennsylvania Railroad T1 and T1a Duplex - Revivaler
Duplex Drive Locomotives.
Pennsylvania Railroad class T1 - Wikipedia
Locomotive Duplex - Wikipedia
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PRR T-1 Duplex Top Speed 140mph (Volume 1) - YouTube