I once travelled by Frontier between Meerut-Jalandhar, that day it was hauled by a WDM3A, the haulage felt very powerful and there did not appear to be any problem, rather it made up the delay of more than 40 mts. I am fond of WDP3As also but DM3As or even DM3Ds are better for this 23 coacher. Nowadays Frontier has 7 AC coaches.