Sorry young man but you must at-least do basic checks before you speak (or as in this case write). 22451/52 halts for 25 mins at Ahmedabad Junction so 2 of your reasons go straight out the window. As far as shortage is concerned, any number of WAP & WAM loco's can be transferred here since it is pure AC sector.
Also once the train arrives at the destination, the loco is not switched off but keeps running in idle mode for hours. You can only guess how much diesel is being wasted.
Fyi,...
more... i had asked a loco pilot about the minimum time required to prepare a loco for departure after attaching it to the train & he told me 10 mins is good enough to complete all checks prior departure.