QLR means LR that is done in a short time being.
Right now the loco that is taking RNC shat up to GMO is reversing its direction and then again hauling the train upto RNC and hence it is taking a good amt of time. In case of QLR, a separate loco will be allotted to RNC shat from GMO to RNC. So it will take much less time for LR at GMo if two separate locos will be allotted as reversing of loco is not involved in that and hence it is called QLR (quick loco reversal)