Hey, they're mostly General Railway Signal's NX system, the first intelligent user interface ever. It takes a huge number of big relays to express all the logic, but it's a good system. Everything in rail control since NX looks a lot like NX, even if it's on a screen.
Before NX, someone had to manually set up routes through an interlocking, setting all the switches and signals. The interlocking machine would prevent conflicts (the levers would not move when pulled) but the dispatcher had to figure out the routes. With NX (eNtry eXit), you push a button to select the track on which a train is approaching. Lights then light up for all the places it can exit the interlocking. The system takes into account other trains, previously set up routes, and even switches and track locked out of service for maintenance. You push one of the exit lights. The system then sets up all the switches and signals to get the train out of the interlocking at the desired exit. As the train progresses along the path, the resources (track sections and switches) are released behind it, and become available for other trains.
NX works well. Many later systems were worse. BART had big problems with their 1960s advanced electronic system, which had to be replaced.
(That video shows an older lever system. That's the only one on the NYC subway system.)
Before NX, someone had to manually set up routes through an interlocking, setting all the switches and signals. The interlocking machine would prevent conflicts (the levers would not move when pulled) but the dispatcher had to figure out the routes. With NX (eNtry eXit), you push a button to select the track on which a train is approaching. Lights then light up for all the places it can exit the interlocking. The system takes into account other trains, previously set up routes, and even switches and track locked out of service for maintenance. You push one of the exit lights. The system then sets up all the switches and signals to get the train out of the interlocking at the desired exit. As the train progresses along the path, the resources (track sections and switches) are released behind it, and become available for other trains.
NX works well. Many later systems were worse. BART had big problems with their 1960s advanced electronic system, which had to be replaced.
(That video shows an older lever system. That's the only one on the NYC subway system.)