Complex sentence: The nominally independent Shildon Tunnel Company had dug a tunnel through the hills at Shildon to the Wear basin and after laying of track, South Church station, south of Bishop Auckland, opened in May 1842.
Split into simpler sentences: The nominally independent Shildon Tunnel Company had dug a tunnel through the hills at Shildon to the Wear basin. After laying of track South Church station, south of Bishop Auckland opened in May 1842.