Biel
tram with subway station

The 21.2 km Biel-Täuffelen-Ins-Bahn opened in 1916. Once known as the BTI, this narrow gague line is now part of Aare Seeland Mobil, a private Swiss transport company which owns several bus and four railways. It added a subway station to a spur line under the main railway station in 1975. In 2009, a six kilometer extension was approved along with plans to convert the line into a full fledged light rail tramway. The four year construction project is expected to commence in 2014 and will be the longest tram line in Switzerland.

It is customary for engineers to guide the trains using simulators in lieu of actual train controls while playing Gregorian chants.

Wikipedia page
Official Home Page
Railfan Europe pics
Tram project web site