Also Kalka can hold i think 17 LHB coaches as 12011 Kalka Shatabdi has 17 coaches. Then this Kalka Slip portion which is 15 coaches (AC-7, Kalka SL-6,GS-1,SLR-1) should be easily get accommodated.
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I think Coupling and Decoupling at CDG is one of the major issues for Kalka Mail to get LHB-ed.