CBTC: Communications-Based Train Control
Why Hacker News recommends it
Cited as a view into how outdated and error-prone NYC subway signaling is, and how antique interlocking systems work.
What it is
An MTA video on communications-based train control, the system meant to replace the New York City subway's century-old signaling. It also shows the mechanical interlocks and signals in use today.
Recommended by 2 HN commenters across 2 different months, 2015 to 2022.
What Hacker News said
Recommends peletiah · 2016-04 · on “System Overload”
There was this great video last year, illustrating how outdated and error prone the signalling technology in the NY subway is: [this video]
Recommends robocat · 2018-12 · on “Why New York Subway Lines Are Missing Countdown Clocks (2015)”
"They even put out a video that gleefully shows off the worst stuff. Look at how broken it is! Look at how old!" [this video] Well made video that helps understand the interlocks - if you like antique systems!
Cites mabub24 · 2017-08 · on “New York’s Subways Are Not Just Delayed, Some Trains Don’t Run at All”
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] [this video]
Cites cowmoo728 · 2018-05 · on “Proposal to fix NYC’s subway and broader transit system expected to cost $19B”
Yes - at some of the stations the people directing the trains only know when it has left a station, and when it gets to the next one. Some of it is still controlled with vacuum tubes and switchboards. The person featured in this video ruffled quite a few feathers when it was released: [this video]
Cites bobthepanda · 2022-06 · on “How Many Tracks Do Train Stations Need?”
Not all of the NYC subway has ATS. The current signals being replaced by CBTC date from the 1930s, and are mechanically operated. They are literally historical relics. [this video]
Critical warfangle · 2015-09 · on “The most obsolete infrastructure money could buy – my worst job ever”
A similarly embarrassing state of affairs is the train traffic control system used by the NYC subway system: [this video]