This is the best that appeared in the subway over the past year – it is strange that no one talks about it.
In the past, at the subway stations, a board was installed showing the time of departure of the previous train. Many passengers thought that this information was intended for them – and complained that it was not very useful. In fact, it was intended for machinists (therefore, the board and hung just opposite his cabin), so that they understand whether they are lagging behind on schedule or not – there was no single informational online system between the trains.
The last year in the Moscow metro at some (not at all, mostly at new) stations, a scoreboard with a timer is set before the arrival of the next train. I met them quite often, and according to my observations, they show accurate information – the error there is only a couple of seconds.
In general, trains in the Moscow metro run frequently, and even if the train left right in front of you, the next one will come in a couple of minutes. But sometimes it is useful to understand that you need to hurry to the platform if the arriving train is not visible, say, from behind the columns.
The only thing: it is not clear when these boards will appear on all stations. In January 2017, the authorities promised to do everything by July 2017, but still have not finished their work.