At any point in time, a finite amount of time has passed, and the trolley has killed a finite amount of people. The correct track is the one that, at any given time, will have killed fewer people. Unless the trolley speeds up to account for that and always kills n people per second, the top track will result in less deaths over any period of time.
The tram travels at light speed and so time no longer flows for you. You exist in a singular moment of splattergore.
All trolleys to date have been finite. A trolley which can kill an infinite number of people would truly be a marvel of engineering.