When's It Coming

I first saw signs saying when the next train is coming in Russia. Then I saw them in DC. Then I saw them on the L train in New York. And yesterday I say them on the 6 train, which I used to ride every day to high school:

In my view providing this kind of information is a total game-changer for mass transit. In Amsterdam the streetcar stops have similar information and in Germany it's frequent to provide this sort of data at bus stops. Adding this to buses is, in particular, a relatively low-cost way of adding a ton of value to your city's transit system.