Complex sentence: The process of change was accelerated by the East London line extension, now part of London Overground, and the reopening of Dalston Junction railway station, part of London's successful bid to host the 2012 Olympics.
Split into simpler sentences: The process of change was accelerated by the East London line extension, now part of London Overground. The reopening of Dalston Junction Station on this extension was part of London's successful bid to hold the 2012 Olympics.