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> There should never be the case when it says a train is 8 minutes away and a train behind it is 9 minutes away when a train gets to the station in 2 minutes an

> There should never be the case when it says a train is 8 minutes away and a train behind it is 9 minutes away when a train gets to the station in 2 minutes and the train behind it gets to the station in 5 minutes. This is like complaining about a car trip taking less time than Google Maps predicted, due to an accident ahead of you getting cleared up before you reach that stretch of road. Unpredictable things happen on public transit: sick passengers, police activity, signal problems, mechanical failures, cascading delays causing platform crowding and longer board times. These things cause delays, and then on the tail-end of the event, sometimes they cause trains to be "early" when the delay clears up. Even then, though, in my experience it's pretty rare that the train comes before the time on the countdown clock. All things considered, I find the countdown clocks to be pretty accurate a vast majority of the time. And they're certainly a huge improvement over how things were before they were installed: a loud beeping noise about a minute before the train arrived, sometimes paired with a muffled inaudible announcement from the station attendant over an ancient PA system.

notyourday 7y ago
So about 30 minutes after I posted it I'm on the L and there's a train to Lorimer at in 8 minutes, train to Manhattan in 19 minutes. That's on the countdown clock. This will put the Manhattan train above the Broadway Junction. There's an announcement on the loud speaker that there's no service between Broadway Junction and Canarsie in both directions because of police activity. Two minutes later, according to the count down clock there's a train to Lorimer in 6 minutes and to Manhattan in 17 minutes. Followed by 5 - 16 and 3 - 13. There's still an announcement that there's no service between Broadway Junction and Canarsie in both directions. But there are magical countdown clock connected trains that will be now here in 3 minutes and 10 minutes. Oh wait, the magical clock is saying there's a train entering a platform! It is going to Lorimer and it is followed by a train to Manhattan! The clock is at zero and it is blinking! All aboard the subway track! This went on for about 40 minutes. Twitter says there's no service. Countdown clock says there's a train coming! Google transit says there's no train. Countdown clock says there's one! And when the service was restored the countdown clock said the next train was going to Lorimer and it was finally 6 minutes away. Except that a train to Manhattan was pulling into the station. The countdown clocks are garbage because the only time that they matter is when there are sick passengers, police activity, mechanical failures and cascading delays -- otherwise we know the train will be here in about ~4-5 minutes and that's exactly the time when the countdown clocks cannot provide reliable information. MTA should finish that project and make it work. After that they can pick their next "digital initiative"
- evanelias 7y ago
  The L train is pretty hosed on nights and weekends until summer 2020. Yes, the countdown clocks specifically on the L are often wrong on nights/weekends during this project. It's not surprising. Do you have an example on a line that isn't undergoing a historic multi-year construction project?
  - notyourday 7y ago
    Sure. G. It is always fun to watch the train on Lorimer heading towards queens to be 13 minutes away just to see it arrive. The point is it does not matter if the L is going through the historic reconstruction project -- countdown clock should depend on two pieces of real time data and one piece of historic ( same trip data ) from previous sections: 1. Position of the train which is always known on the L because it is an ATC line. 2. Speed of the train. Also known because it is an ATC line. The distance between stations is fixed. The data about speed and the distance train covered at t-1 and t-2 is known. So it is algebra + basic message passing architecture + LCD displays connected to the local systems. 2. Speed of the train

notyourday 7y ago

So about 30 minutes after I posted it I'm on the L and there's a train to Lorimer at in 8 minutes, train to Manhattan in 19 minutes. That's on the countdown clock. This will put the Manhattan train above the Broadway Junction. There's an announcement on the loud speaker that there's no service between Broadway Junction and Canarsie in both directions because of police activity. Two minutes later, according to the count down clock there's a train to Lorimer in 6 minutes and to Manhattan in 17 minutes. Followed by 5 - 16 and 3 - 13. There's still an announcement that there's no service between Broadway Junction and Canarsie in both directions. But there are magical countdown clock connected trains that will be now here in 3 minutes and 10 minutes. Oh wait, the magical clock is saying there's a train entering a platform! It is going to Lorimer and it is followed by a train to Manhattan! The clock is at zero and it is blinking! All aboard the subway track! This went on for about 40 minutes. Twitter says there's no service. Countdown clock says there's a train coming! Google transit says there's no train. Countdown clock says there's one! And when the service was restored the countdown clock said the next train was going to Lorimer and it was finally 6 minutes away. Except that a train to Manhattan was pulling into the station. The countdown clocks are garbage because the only time that they matter is when there are sick passengers, police activity, mechanical failures and cascading delays -- otherwise we know the train will be here in about ~4-5 minutes and that's exactly the time when the countdown clocks cannot provide reliable information. MTA should finish that project and make it work. After that they can pick their next "digital initiative"

evanelias 7y ago
The L train is pretty hosed on nights and weekends until summer 2020. Yes, the countdown clocks specifically on the L are often wrong on nights/weekends during this project. It's not surprising. Do you have an example on a line that isn't undergoing a historic multi-year construction project?
- notyourday 7y ago
  Sure. G. It is always fun to watch the train on Lorimer heading towards queens to be 13 minutes away just to see it arrive. The point is it does not matter if the L is going through the historic reconstruction project -- countdown clock should depend on two pieces of real time data and one piece of historic ( same trip data ) from previous sections: 1. Position of the train which is always known on the L because it is an ATC line. 2. Speed of the train. Also known because it is an ATC line. The distance between stations is fixed. The data about speed and the distance train covered at t-1 and t-2 is known. So it is algebra + basic message passing architecture + LCD displays connected to the local systems. 2. Speed of the train