WDP-4/4B/4D, yeh sab are following their parent style, jo Desi nahi hain. so u can see the same power, traction and but difference in gear ratios.
Even WDG-5, the silent loco, has the same specs of American SD-70MAC. almost all EMD's of Indian railways are following the suit of American ones.
After all, the parents dna is often carried in kids.