Helsinki
Helsinki
http://www.hel.fi/wps/portal/helsinki_en/?wcm_global_context=/en/helsinki/
Kopenhagen
Kopenhagen
http://www.m.dk/
Oslo
As oslo sporveier is a service company responsible for planning, managing, marketing and operating oslo’s public transportation system, as well as some lines that extend beyond the city limits.
http://www.sporveien.no/templates/page____180.aspx
Stockholm
Stockholm
http://www.sl.se/