One of the <a href="//commons.wikimedia.org/wiki/Edinburgh_Trams" title="Edinburgh Trams">Edinburgh Trams</a> heading west along Princes Street (away from the camera), en route to the <a href="//commons.wikimedia.org/wiki/Category:Edinburgh_Airport_tram_terminus" title="Category:Edinburgh Airport tram terminus">Airport terminus</a>. It's crossing the junction with Waverley Bridge, about to pass Scott Monument on the left. The <a href="//commons.wikimedia.org/wiki/Category:Princes_Street_tram_stop" title="Category:Princes Street tram stop">Princes Street stop</a> is still some distance ahead - passengers wanting Waverley mainline railway station (out of shot to the left) are advised to get off at <a href="//commons.wikimedia.org/wiki/Category:St_Andrew_Square_tram_stop" title="Category:St Andrew Square tram stop">St Andrew Square stop</a>. Note the row of white vertical lights below the green light on the right hand set of traffic lights - this is a dedicated signal for the tram, telling it to proceed.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/25034321@N05">Ninian  Reid</a> from Perth, Scotland
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/ninian_reid/14497633644/">DSCN0025</a>