This article is somewhat out-of-date. The L & 7 trains were modernized to communications-based train control (CBTC) & automatic train operation (ATO) since 2006 & 2018 respectively. This allows for moving-block signaling, where a trains are separated by a distance, instead of fixed blocks of track. The legacy fixed-block signaling system is still retained as a fallback.
Can confirm. While the CBTC already existed, I worked on the ultra-wideband positioning system originally demoed on the 7 line (and spent a lot of sleepless nights riding empty 7 line trains, testing out the system). I wrote the original version of the system that would initiate the time-of-flight signals to the trackside UWB beacons and use multilateration to determine the train position (of both extreme ends of the…
Re: NYC Subway Signals: A Complete Guide (2012)
#11Whatever became of the UWB positioning system? The trials appeared to be successful, but to my knowledge the system has not yet been adapted in NYC or elsewhere.