Complex sentence: The Bexleyheath Line runs for 8 miles (13 km) from to Dartford in Kent operating between the North Kent Line just to the east of Blackheath station and to the same line south of Slade Green in Dartford.
Split into simpler sentences: The Bexleyheath Line runs for 8 miles (13 km) from to Dartford in Kent. It separates from the North Kent Line just to the East of Blackheath Station, and rejoins the same line just South of Slade Green in Dartford.