This is how they could drastically increase the passenger capacity of that boring loop:
It takes ten times as many passengers as a Tesla model X but doesn't cost more. (and goes about the same speed as they drive in those tunnels!)
__________________
2016: 128.75L for 1875.00km => 6.87L/100km (34.3MPG US)
2017: 209.14L for 4244.00km => 4.93L/100km (47.7MPG US)