For this reason , though similar to the existing Class 08 shunting locomotives , Class 09s were re-geared to give a maximum top speed of 27.5 mph ( 44 km\/h ) at the expense of a lower tractive effort . Though similar to the existing Class 08 shunting locomotives , Class 09 were re-geared to give a maximum top speed of 27.5 mph ( 44 km\/h ) at the expense of a lower tractive effort .