About The East Coast Line (Swedish: Ostkustbanan) is a 402-kilometre (250 mi) long mainline railway in Sweden, linking the cities of Stockholm, Uppsala, Gävle and Sundsvall, as well as the suburbs north of Stockholm. The first part of the line was electrified in 1906–07 as a part of SJ's electrification trials. In 1926, the Western Main Line between Stockholm and Gothenburg was electrified. As Stockholm's main train depot is located in Hagalund, on the East Coast Line, this part was also electrified at the same time. The whole line was finally electrified in 1934. As all other lines in Sweden, East Coast Line is electrified with 15 kV 16.7 Hz AC. This line has both local and fast passenger services as well as freight traffic. Rollingstock ER1 (Stadler kiss) X3 ( Alstom Coradia) X40 (Alstom Coradia Duplex) X55 (bombardier Regina) X60 (Alstom Coradia Nordic) Rc 193 (Vectron) 142 X2000 (not sure if this runs on the line) Videos
Stockholm-Gävle or even Sundsvall is probably too long for TSW, but Stockholm-Uppsala (including the line via Arlanda airport) would be a good route length, with a nice variety of scenery, services and rolling stock. Somehow I doubt we'll ever see a Swedish route though...
Uppsala - Gävle or Uppsala - Stockholm would be good length all the way to sundsvall would be to much work