Complex sentence: The change of gauge at Gloucester meant that everything had to be transferred between trains, creating chaos, and the C&GWU was owned by the Great Western Railway, which wished to extend its network by taking over the Bristol to Birmingham route.
Split into simpler sentences: The change of gauge at Gloucester meant that everything had to be transferred between trains, creating chaos. Morever, the C&GWU was owned by the Great Western Railway, which wished to extend its network by taking over the Bristol to Birmingham route.