WAP-5 is known for it's speed (Max Speed Potential : 200 Kmph) as it is usually meant for hauling medium load trains like Rajdhanis & Shatabdis . On the other hand , WAP-7 is known for it's power as it is usually meant for hauling heavy load trains like 20+ Coach Long Distance Non - Rajdhani Trains (Max Speed Potential : 140 Kmph) . If you want a combination of both speed and power then it's got to be a Diesel Dippy which is the WDP-4 Loco (Max Speed Potential 180 Kmph and can also haul heavy load trains but not at such high speeds due to Present Indian Track Conditions) . Thanks for asking this question .