|Coal Power. Here is a duplicate 35mm color slide showing (L to R) Pennsylvania Railroad engines #6717 and #5872. #6717 is an M-1B (4-8-2) "Mountain" built by the Baldwin Locomotive Works as an M-1A during April of 1930, rebuilt in Juniata as an M-1B in March of 1948, and retired in September of 1958. #5872 is an EP-20 built by GM-EMD in April of 1949 and rated at 2,000 horsepower. Symbolically speaking, oil power is about to eclipse coal power forever! The photographer's name, the date, and the location are not recorded.