Context: The first streetcars appeared in 1889 and were instrumental in the creation of a relatively well-defined downtown and strong neighborhoods at the end of their lines. The advent of the automobile sounded the death knell for rail in Seattle. Tacoma–Seattle railway service ended in 1929 and the Everett–Seattle service came to an end in 1939, replaced by inexpensive automobiles running on the recently developed highway system. Rails on city streets were paved over or removed, and the opening of the Seattle trolleybus system brought the end of streetcars in Seattle in 1941. This left an extensive network of privately owned buses (later public) as the only mass transit within the city and throughout the region.

Question: In what year were the first streetcars used in Seattle?
Answer: 1889

Question: What machine caused the end of city rail lines in Seattle?
Answer: automobile

Question: When did the Tacoma-Seattle rail service end?
Answer: 1929

Question: In what year did the Everett-Seattle rail lines cease?
Answer: 1939

Question: The use of what caused the end of the use of streetcars in 1941?
Answer: trolleybus