This resulted in the introduction in 1919 of 23 G3a class 4-6-2s with seventy five inches (1,905 millimetres) driving wheels, built by Angus for assistance more than flat terrain, and five G4 course locomotives with scaled-down 70 inches (1,778 millimetres) drivers, built by Montreal for hilly terrain. The locomotive used saturated steam and had 1,250 millimetres (49.