Helsinki has one for their trams, subway and ferries:
<a href="http:&#x2F;&#x2F;live.mattersoft.fi&#x2F;hsl&#x2F;Default.aspx?lang=en" rel="nofollow">http:&#x2F;&#x2F;live.mattersoft.fi&#x2F;hsl&#x2F;Default.aspx?lang=en</a><p>I <i>really</i> wish there was this service for buses. Quite often the digital displays saying when the bus will arrive are inaccurate, as are the actual timetables printed on the bus stop (when there is traffic etc.)