Thanks for sharing few points which I am unaware of, but only one thing which I have observed is - speed is certainly increased by attaching dual engines because, inspite of so many crossings, trains with dual engines manage to cover the travel time between parbhani to aurangabad in 2 hrs 50 min. Quoting this from my personal experience past few trips. If you see the same MLY loco go with Karnataka SF exp as there is LSA between Devagiri and Karnataka loco. There are few incidences of loco failure, but that is comparatively less and is common as it is observed in many other parts of India as well even in CR we observe loco failures may be diesel or electric. At the end its a machine and can develop fault sometime.