Turns out Teslas are cheaper per passenger seat than a subway car plus have less requirement for specialized infrastructure (rails, etc). So if TBC is gonna be doing the whole project, they intend to use Teslas. It’s not a bad engineering choice. With automation (not hard in a tunnel), can achieve similar throughput as a Subway.
Minimum train space with pretty standard signaling can be as low as 90s. With modern moving block systems that can be pushed even lower. The tube trains have a seating capacity of around 250 people and 800 people can be standing. This gives a capacity of between 3 and 12 people per second.
How are you going to inject 1 car per second (to reach the lower level) into the tunnel in a safe way? And even if you could do it - Consider how huge the stations must be. They have to contain 100+ cars plus space to enter/exit them (couple seconds to come to a stop, 10s of seconds to leave the vehicle - with some people quicker than others -, 10s of seconds for other people to enter the vehicle, couple seconds to accelerate and synchronize to the flow..).
Folks who dismiss getting subway-like throughputs haven’t actually done the math.
Sub-2 second spacing is quite unlikely to be used, since stopping distance (with 0 reaction time, which is not too unreasonable with LIDAR/RADAR) dictates around 2s spacing between vehicles (1.9s at 100km/h for teslas I believe). And while humans might be fine with ignoring safety aspects computers can't and shouldn't.
Nevermind that building a subway-light vehicles (more similar to a people mover) is not really the same thing as using slightly-modified Teslas as subway replacement (which is what it seems they will be using for now)..