We met outside Edmonds station and walked over to the very secure yards and we had to clear security and I was even scolded for taking a photo on my phone (though, luckily, we were allowed to take photos once we were inside).
Our first stop once inside was a boardroom for a presentation about the system. For instance, the Expo and Millennium lines carry the same amount of people as 12 lanes of freeway in the AM peak period in the downtown direction. It has grown from 114 cars in 1987 to 258 today. But enough about the boring stuff.
He also explained that the system is super safe. The train all have multiple computers on them that work on consensus-like model. If one says something is wrong, the other computers (they may have up to 3) verify the situation and if they think that computer is whack (technical term), the train continues on its merry way. If all the computers are down or they all agree something is wrong, the train stops and is taken out of service.
From Stephen Rees: Of course a computer on a Mark I is "old timer" - the cars are over 20 years old. And the word you are looking for is "axle". Conventional trains do not need steerable axles as the wheels are conical. The axles can tilt through curves. A steerable axle is needed on trains that use the linear induction motor as the gap tolerance between "stator" and "rotor" of a LIM is so small. *EDIT*