And also grade is high between lku-hdw and even higher between hdw-kgm so a wdm3a cannot pull such a long rake from lku to kgm. Wdp4d is needed in 17 coach rakes. See examples of ranikhet express or bagh express or Uttarakhand sampark krani etc wdm 3a can pull 10 or 12 cocach rake easily and 14 is limit for them here. After that they are very uneasy with that.