Escort
From Liquipedia Overwatch Wiki
Escort map objectives require the attacking team to escort a payload vehicle through the map to a destination before a timer expires.
Each attacker within range of the payload, up to a maximum of three, will increase its speed. If any member of the defending team is in range of the payload, the payload stops. If the attacking team is not in range of the payload for 10 seconds, it starts moving slowly backwards.
Along the way, the payload reaches checkpoints that add time to the attacking team's time bank. Once the payload has reached a checkpoint, the payload cannot move further back than that checkpoint anymore.