WAP-4 are being phased out. And all the loco crews are trained for 3-phasors. Hence WAG-9 is the best choice.
Regarding WAP-5, it is limited to 3 sheds only so their operational zone is limited.
And yes there is acute shortage of WAP-7 links due to late running of trains.
please wait...Translate to HindiWAP-4 ko slowly slow phase-out kar rahe hai. Aur saare loco crews 3-phasor pe train kiye ja rahe hai. Isiliye WAG-9 sabse acchi choice hai.
WAP-5 ke baare mein, woh sirf 3 sheds mein limited hai, isliye unka operational zone bhi limited hai.
Haan, WAP-7 links ki bhi bahut shortage hai kyunki trains late chal rahi hai.