Complex sentence: The station was the southern terminus of G until July 5,2009, when the G was extended south at all times to Church Avenue, to allow for overhaul of the Culver Viaduct.
Split into simpler sentences: The station was the southern terminus of G service until 2009. On July 5,2009, the G was extended south at all times to Church Avenue, to allow for overhaul of the Culver Viaduct.