This might seem like a cool idea at first. But, why they did not built an elevated metro/sub-way line. I don't think this kind of vehicle is energy efficient.

This might seem like a cool idea at first. But, why they did not built an elevated metro/sub-way line. I don't think this kind of vehicle is energy efficient. The aerodynamics of the vehicle doesn't seem to be very good. That amount of energy can carry more people and be energy efficient(compared to this) for a regular metro/sub-way or trams.