|
The Robertson Tunnel is a twin-bore light rail tunnel through the Tualatin Mountains west of Portland, Oregon, used by the MAX Blue and Red Lines. The tunnel is long〔''Light Rail and Modern Tramway'', November 1993, p. 302. UK: Ian Allan Publishing/Light Rail Transit Association.〕 and consists of twin -diameter tunnels. There is one station within the tunnel at Washington Park, which at deep is the deepest subway station in the United States and the fifth deepest in the world.〔 〕 Trains are in the tunnel for about 5 minutes, which includes a stop at the Washington Park station. The tunnel has won several worldwide engineering and environmental awards.〔(【引用サイトリンク】 Awards & Recognition )〕 It was placed into service September 12, 1998.〔(【引用サイトリンク】 Westside MAX Blue Line Project History )〕 The tunnels pass through basalt layers up to 16 million years old. Due to variations in the rock composition, the tunnel curves mildly side to side and up and down to follow the best rock construction conditions.〔(【引用サイトリンク】 Westside light rail—the MAX Blue Line extension )〕 The tunnels vary from 80 to 300 feet (24–91 m) below the surface. A core sample taken during construction is on display with a timeline of local geologic history. The east tunnel entrance is near Vista Bridge at the edge of the Goose Hollow neighborhood at the foot of Washington Park. The west entrance is along U.S. Highway 26 just west of the Finley-Sunset Hills cemetery, about a mile east of the junction with Oregon Highway 217. == Name == The tunnel is named for William D. Robertson, who served on the TriMet board of directors and was its president at the time of his death. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Robertson Tunnel」の詳細全文を読む スポンサード リンク
|