The Coast Tram is a public transport service connecting the cities and towns along the entire Belgian (West Flanders) coast, between De Panne near the French border and Knokke-Heist near the Dutch border. At 67 km (42 miles) in length, it is now the longest tram/light rail line in the world, as well as one of the few interurban tramways in the world to remain in operation. 

The service makes 67 stops along the ca.67 km line, with a tram running every 10 min during the peak summer months (every 20 min in the winter months), and it is used by over 15 million passengers per year. 

Interesting features are the sea-view between Oostende and Middelkerke, the tracks through the dunes at De Haan, the high-speed, and the two alternative routes that exist around both ends of the Leopoldkanaal locks, just east of Zeebrugge, and the similar single track diversion around the inland end of the Boudewijnkanaal lock.


That avoids delays when the road bridge that the tram line normally follows is raised for boats passing under it. 

According to en.wikipedia