Oh dear :cry:.
I suppose the dead 66 could be started up as and when needed if not too often. l am fearing that, if the test is successful, DBS could have two 66s on the heavy trains with the dead one only being started up in extreme cases of wheel slip or lack of tractive effort. That might well save fuel over a 60. It is not as though DBS are short of 66s to drag around dead all day but I wonder if that is more economical.