I’m an armchair transit specialist, and I do not know specifically, but generally, it would seem the cost for each additional passenger on a transit system foll

I’m an armchair transit specialist, and I do not know specifically, but generally, it would seem the cost for each additional passenger on a transit system follows a step function such that n + 1 < $0.01 until you hit ‘capacity’, a loosely defined term at which point the next passenger causes losses (congestion and delay boarding and disembarking). In a properly running system, the fixed costs dramatically outweigh the additional burden of each passenger, in the same way that the bus engine hardly noticed the additional weight of another 170 lb passenger relative to the 40,000 lb bus. Even with consumables like ticketing, the whole revenue system far outweighs the increment.