I think we're getting side-tracked by trying to define the word "hauling".
It doesn't really matter if the correct term is hauled, pulled, towed, dragged or something else. What I can't understand, if the only problem was a faulty horn, why the engines of the 150 and 156 were not being used in multiple with the 142 in order to provide power for the whole train .
No wonder it was running late if the 142 was being asked to tow, sorry haul
, a trailing load of 146 tonnes + passengers.