One of the Edinburgh Trams heading west along Princes Street (away from the camera), en route to the Airport terminus. It's crossing the junction with Waverley Bridge, about to pass Scott Monument on the left. The Princes Street stop is still some distance ahead - passengers wanting Waverley mainline railway station (out of shot to the left) are advised to get off at St Andrew Square stop. 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.