Sir you are mistaken!
1. Wear and tear are there is every locomotives. Do diesel locomotives need more care ? Yes they do, but they are a lot more reliable. The WAP-7s are a lot less reliable atleast, they were until a few years ago.
2. WDP-4s can do 130 quite easily. Infact they are certified for 160 kmph. WAP7s are allowed to go upto 140kmph. WAP5s except the modified ones are rated for 160 kmph
3....
more... WDP4 was selected for Talgo instead of the WAP5 locomotives because IR wasn't confident that OHE could withstand a P5 doing 180 kmph.