New York City subway infrastructure: relays, switching, etc...

[Krcwell]

I found the first 3.5 minutes of this video fascinating. The NYC subway is basically a giant mixing console sending analog signals via relays and switches everywhere.

http://youtu.be/Mjx3S3UjmnA

 

[sahib]

Enjoyed it. I hope they make a record of the "old" technology before all replaced. A few years back I archived  (I was told) the oldest remaining electric crane in the UK literally a day before it was scrapped.  Drive motor was DC supplied by 2 x  mercury arc rectifier aka Hewittic Rectifier. By luck a year later I bought an original installation and service manual for the rectifier by the original Hewittic Company.

 

[Gene Pink]

Great subway controller gear video, and ya gotta love giant rectifier tubes.

Another one, telephone switching gear explained, in 1951.

https://www.youtube.com/watch?v=xZePwin92cI

It gets good around 1:40 into it.

Gene