Here’s an excellent video presentation of the Paris Tramway line T3 from concept to reality. From the computer renderings, stages of construction, before and after construction scenes, delivery of the trams, to the finished product, it ends with a time-lapse cab view test ride on the line.
The 7.9 km, 17 station line runs along a peripheral boulevard on the southern edge of Paris proper. The line began construction in 2003 and opened in 2006 at a cost of 311 million euros ($400 million US at 2006 rates). It took away 2 traffic lanes from the boulevard and replaced one of the busiest bus routes in Paris. It currently carries 100,000 riders every weekday at an average speed of 18 km/h (target 20 km/h) with trains running every 4 minutes during peak hours. Trains get signal priority. The RATP expects to reduce traffic on the boulevard by 25%. Parks, cycle tracks, public art, and a grassed trackway help the tram integrate well into the urban fabric.
You can also tour the line with Google Street View.
In comparison, it is a mile longer than the proposed Seattle Streetcar Central Line and the Link light rail surface segment between Mount Baker and Rainier Beach stations. It has more than 4 times the stops and half the average speed of that Link segment.