PAX INJURIES SUSTAINED DURING ACFT PARKING PROC.

Narrative

ARRIVED AT PARKING GATE AT EWR. I SET PARK BRAKES AND WAS VERIFIED BY FO. I ORDERED THE R ENG SHUT DOWN AND TURNED THE SEAT BELT LIGHT 'OFF.' L ENG WAS LEFT RUNNING (APU SHUTDOWN). FO LOOKED UP AND YELLED 'WE'RE ROLLING!' IMMEDIATELY HIT THE BRAKES RESULTING IN AN ABRUPT LURCH. AFTER 3 OR 4 ATTEMPTS TO RESET BRAKES WERE UNSUCCESSFUL; I HAD THE FO ATTEMPT TO SET THE BRAKES. THEY ALSO WERE UNSUCCESSFUL. AFTER SELECTING 'RESERVE BRAKES' I WAS ABLE TO RESET THE PARKING BRAKE. HYD BRAKE PRESSURE WAS NORMAL. I STARTED THE APU AND SHUT DOWN THE L ENG. THE TOW BAR WAS HOOKED UP AND ACFT REPOSITIONED. PAX RPTED BEING JOSTLED AND SOME MINOR INJURIES. CONTRIBUTING FACTORS: 1)PRACTICE OF LEAVING 1 ENG RUNNING AT GATE WAITING FOR GND PWR TO SAVE APU FUEL. 2) DELAY IN CHOCKING WHEELS AS SOON AS THE ACFT IS STOPPED. 3) FAILURE OF PARKING BRAKE MECHANISM. SOME CORRECTIVE RECOMMENDATIONS MIGHT BE: 1) DISCONTINUE PRACTICE OF LEAVING ENG RUNNING AT GATE. 2) ENSURE WHEELS ARE CHOCKED AS SOON AS ACFT IS STOPPED. 3) INVESTIGATE FAILURE OF PARKING BRAKE LINKAGE.