Complex sentence: One, operated by Arriva Trains Wales, runs between Birmingham International and Shrewsbury, with alternate trains continuing to Aberystwyth or Holyhead; the other by London Midland between Shrewsbury and Birmingham New Street, which call at all stations between Shrewsbury and Wolverhampton.
Split into simpler sentences: One, operated by Arriva Trains Wales, runs between Birmingham International and Shrewsbury, with alternate trains continuing to Aberystwyth or Holyhead. The other trains are London Midland services between Shrewsbury and Birmingham New Street, which call at all stations between Shrewsbury and Wolverhampton.