Akersgata 65, whereas the worker class lived in wooden houses in the suburbs. In that time, wealthy people moved from what would become the East End to the new West End, professors from the university buildings in Tøyen, factory owners from Sagene, officials from Gamlebyen, people in the city gardens in Kvadraturen which became shop buildings etc. In the East End, the population became more homogenous than before: new immigrants from Eastern Norway and original citizens built the new worker class in the city of Kristiania together, affecting the growing industry, handwork, transport, and other areas. Around 1880 the division between the East End and the West End was prominent but not complete. In this early stage, new apartments for wealthy people in areas such as Gamlebyen (Schweigaards gate) were built, and it was attractive to settle down in Kvadraturen. The expansion of the city in the 1890s strengthened the division and the systematic boundary line. In 1910, the average income in Sofienberg was a tenth of that in Frogner. Open communications made it possible to live further away from one's working place than before. Horse-driven trams were opened in Homansbyen and Gamlebyen in 1875 and in Grüneløkka in 1878, and electric trams were taken into use in 1894 and had new lines constructed for them. This affected the development of the new areas with socially and economically homogeneous population. Middle class areas The areas to the north of the city centre belong to the West End, but they became very early, and still are, reflected by the middle class, having many officials, high education, and few rich people. These areas include Meyerløkka, Gamle Aker, St. Hanshaugen, parts of Ila, Bolteløkka, Valleløkken, Fagerborg, Lindern and Adamstuen. The villa suburbs of today's outer town grew up along the new railway, and had about 12,000 inhabitants in the early 20th century, in the west Lysaker, Skøyen, Bestum, in the east Bryn, which was the first in the city from the 1860s, Grorud, Bekkelaget, Nordstrand, Ljan - with mixed inhabitants, with no marked East End character. Worker areas in the West End Some worker areas can be found in the West End: Balkeby in Hegdehaugen was a philanthropic worker apartment project built in the 1860s, but lost this character after a large fire in 1879. Briskeby grew up from the 1840s, outside the new city border that followed along Briskebyveien. A couple of