Complex sentence: Withdrawals commenced in 1908 when one locomotive was broken up for spares, and others were withdrawn at intervals until May 1914, when the increased need for locomotives during the First World War meant that there were no further withdrawals.
Split into simpler sentences: Withdrawals commenced in 1908 when one locomotive was broken up for spares, and others were withdrawn at intervals until May 1914. However the increased need for locomotives during the First World War meant that there were no further withdrawals.