Passage: Adelaide was Australia's third largest city for most of the 20th century. Electric street lighting was introduced in 1900 and electric trams were transporting passengers in 1909. 28,000 men were sent to fight in World War I. Historian F. W. Crowley examined the reports of visitors in the early 20th century, noting that "many visitors to Adelaide admired the foresighted planning of its founders", as well as pondering the riches of the young city. Adelaide enjoyed a postwar boom, entering a time of relative prosperity. Its population grew, and it became the third most populous metropolitan area in the country, after Sydney and Melbourne. Its prosperity was short-lived, with the return of droughts and the Great Depression of the 1930s. It later returned to fortune under strong government leadership.Secondary industries helped reduce the state's dependence on primary industries. World War II brought industrial stimulus and diversification to Adelaide under the Playford Government, which advocated Adelaide as a safe place for manufacturing due to its less vulnerable location. Shipbuilding was expanded at the nearby port of Whyalla.

Question: Adelaid had a form of public transportation in which year?
1909