Complex sentence: The regional rail service, SEPTA, had stopped using the train shed after developing an underground station, but soon after the Pennsylvania Convention Center Authority was initiated and revitalization efforts, including a full restoration fo the market, was well underway.
Split into simpler sentences: The regional rail service, SEPTA, had stopped using the train shed after developing an underground station. Soon afterwards, the Pennsylvania Convention Center Authority was initiated, and revitalization efforts, including a full restoration fo the market, were well underway.