Complex sentence: With only limited capacity south of Bolton, Manchester services were reduced to an hourly frequency, and curtailed at Bolton on Monday to Fridays, whilst weekend services were replaced by buses as Bolton station was also undergoing upgrade work for electrification.
Split into simpler sentences: With only limited capacity south of Bolton, Manchester services were reduced to an hourly frequency, and curtailed at Bolton. On Monday to Fridays, weekend services were replaced by buses as Bolton station was also undergoing upgrade work for electrification.