Rakes of all trains maintained by a particular CDO will have same composition and all rakes will be pooled together......so that trains will not get rescheduled or cancelled due to late running of pairing train.....
for e.g. if all rakes of SC/HYB based trains are standardized and pooled together...then AP will not get rescheduled.......for e.g. if 12724 arrives SC 5-6 hrs late and 12792 arrives RT, for next day's 12723, the rake of DNR SC Exp can be used which will be ready by 6 am......and for SC DNR Exp.....rake of 12724 will be used which will be ready by 10 am....