Thinking about this some more, I still don't understand. If the goal was door safety, why not use the same release systems automatic trains (eg underground) have?
Yeah. It's a completely ridiculous idea. Almost as if the project manager had an idea and pushed it through without thinking about the repercussions.
If it's really a problem why not use the speedometer to figure out if the train is moving? Or why not use something like the MTA's wheel rotation sensors? The guy who wrote the signal code for MTA said that they use wheel rotations to calculate when to play audio messages in-train and in-station... those "There is a queens-bound train N stations away". It's a simple idea.
