The subway of the future puts stations at or near the surface
The design of subways goes back to the late 19th century. Tunnels have virtues, but instead of sending a giant train through them every 5 minutes, in the future we could fill the tunnel with smaller electric vans which go nonstop from station to station (changing lines) and even put their stations at or near the surface for quick access and energy efficiency. Imagine a subway like a modern elevator, where you indicate your destination station and it tells you which van to enter to get there in zero to 2 stops. And let the vans go past the end of the line on surface streets to serve more areas. You can actually have more capacity, comfort, speed and convenience, plus much lower cost.
Read how this can happen in a new Forbes article at The subway of the future puts stations at or near the surface