Castleton was originally the junction for the branch line to Heywood, which was then extended through Bury to Bolton. A connecting line (known as the Bury South Junction Connecting Line or Bury East Fork) enabled trains off the Castleton to Bolton line to run northwards from Bury on the Clifton Junction to Accrington line. The Bacup line left the Clifton Junction to Accrington line at Stubbins Junction. Therefore, the remaining Castleton to Rawtenstall line is combination of remnants of several lines.