You ignored the lifespan of a train vs a Tesla vehicle. Maintenance is also a big cost factor. You can run a train for decades with very low maintenance costs,

You ignored the lifespan of a train vs a Tesla vehicle. Maintenance is also a big cost factor. You can run a train for decades with very low maintenance costs, which is just not true for a car fleet. Your average car would suffer from some critical, perhaps non-repairable condition, at 300,000 miles. Train cars last for decades. > Of course, you can sardine people into trains more than you can squeeze people into cars, but we've ignored the cost of rail, larger tunnels, and large underground stations needed to run subways, and cars can handle load variance more cheaply than trains, which often run near-empty. It seems that you are really concerned about personal space, but anyway. "Larger" tunnels and stations are needed for several reasons, one of them being able to handle passenger volume and accessibility. What you are saying is, essentially, that underground train infrastructure is "more expensive" because it is just better: it can handle more passengers, has to comply with safety regulations, and needs to be accessible.