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Incase you are unaware, the Class 444s (this post) are the five-carriage white units and the Class 450s (Gizmogle's post) are the four-carriage blue units. The main interior differences are the better seats and tables in the the Class 444, and the seat layout. The 444s have 2+2 seating (1+2 in first class) and the Class 450s have 2+3 seating (2+2 in first class).