Complex sentence: Initially, 31 D F locomotives were ordered, but this order was amended to ten D F s and 42 D G class locomotives, which in appearance was essentially half a D F but with a similar Bulldog nose cab design.
Split into simpler sentences: Initially, 31 DF locomotives were ordered, but this order was amended to 10 DFs and 42 DG locomotives. The DG class in appearance was essentially half a DF, with a similar Bulldog nose cab design.