Complex sentence: The Northern Central Railroad was an incredibly important link between Washington, D.C. and points along the northern path all the way to Lake Ontario and upstate New York, serving as an pivotal source for economic prosperity for local farmers and other businesses in York County.
Split into simpler sentences: The Northern Central Railroad was an incredibly important link between Washington, D.C. and points along the northern path all the way to Lake Ontario and upstate New York. The railroad was an important source for economic prosperity for local farmers and other businesses in York County.