Complex sentence: Twelve Class 319s will be cascaded from Govia Thameslink Railway to operate electrified services in the North West allowing Class 142 and Class 144 units to be replaced as well as the Class 37 hauled Mark 2 carriages.
Split into simpler sentences: Twelve Class 319s will be cascaded from Govia Thameslink Railway to operate electrified services in the North West. These will allow for the Class 142 and Class 144 units to be replaced as well as the Class 37 hauled Mark 2 carriages.