The Oslo T-Bane 

The Oslo T-Bane (Short for Tunnelbane, Metro in English) is the metro system in Oslo, Norway. It has 5 lines, which all share track in the common tunnel underneath the city centre, operating similar to an S-Bahn system. These lines also form a ring line around the north of the city.
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Between Jar and Bekkestua on line 3, the system shares track with the Oslo Tramway.
Line 1 climbs up the side of a mountain to cross country skiing trails just outside the city. It reminds me much more of a rural railway than a rapid transit system.
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