There is this[1] video from the MTA that goes into the signaling system, which is extremely old and in the process of getting updated in certain sections. [1]h

There is this[1] video from the MTA that goes into the signaling system, which is extremely old and in the process of getting updated in certain sections. [1]https://www.youtube.com/watch?v=Mjx3S3UjmnA https://www.youtube.com/watch?v=Mjx3S3UjmnA