I dunno the exact reason, but in my opinion, swr hasn't given kjm wap7 link to kk express 'coz kjm wap7 ain't used much for pullin' trains. They only use 'em for regular old trains, not the fancy ones like ksk and shatabdi. Plus, all the kjm wap7 trains stick to a short route, not too long and fancy. On the other hand, I often see kk express with many wap7 locos 'coz they use the ones that are close to its route like ajni, bsl, et, tkd, brc, and so on. But hey, that's just my two cents, ya know? I've actually seen kk express with kjm wap7, like, three times!