Why don't you ask for something better -> WAP7 TRIPLETS :D Just kidding! :P
Two WAP7 locos can be MUed and attached to it from the front side. The remaining WAP7 can be attached to it from the rear side. Two locos out of three can be withdrawn/attached at CBE while exiting/entering Kerala.
As soon as it enters Kerala, it has to halt at each and every station. Also, it has to achieve its MPS too between two halts to maintain schedule.
To...
more... achieve MPS in Kerala :-
* The acceleration power of a single WAP4/7 won't be enough.
* Twins will do very well on plain sections.
* If the above mentioned combo is used, the acceleration will be excellent everywhere, even on steep gradients.