What is so special about this robot?

This is:

The Bay Area Rapid Transit system in San Francisco consists of more than 75 miles (120 kilometres) of track stretching across roughly 30 stations with around 100 trains in simultaneous operation during peak hours. What is most interesting about it?

What security systems do airplane autopilots have:

Can we 3D print medicine?

How fast can this maglev train go (2015)?