Complex sentence: The Lackawanna had operated freight and passenger trains over its railroad profitably for decades, but competition from trucks and other pressures in the post-World War II era forced it to merge with the Erie Railroad (ERIE) in 1960.
Split into simpler sentences: The Lackawanna had operated freight and passenger trains over its railroad profitably for decades. However, competition from trucks and other pressures in the post-World War II era forced the Lakawanna Railroad to merge with the Erie Railroad (ERIE) in 1960.