Pennsylvania Railroad 6755 is a 4-8-2 "Mountain" type steam locomotive built in 1930 for the Pennsylvania Railroad by the railroad's own Altoona Works as a member of the M1b locomotive class for mainline freight service. Retired from commercial service in 1957, the locomotive was preserved by the Pennsylvania Railroad and was placed on display at the Railroad Museum of Pennsylvania in Strasburg, Pennsylvania. The 6755 is the only M1 class locomotive to have survived into preservation.