Complex sentence: Greenhithe station serves the area with services to London Charing Cross both via Sidcup and via Woolwich Arsenal, Gravesend and Gillingham Trains are operated by Southeastern.
Split into simpler sentences: Greenhithe station serves the area with services to London Charing Cross both via Sidcup and via Woolwich Arsenal. These services continue to Gravesend and Gillingham Trains are operated by Southeastern.