03/01/1910 : Avalanche at Wellington, Washington, (Stevens Pass) Kills 118 people, on the Great Northern Railway.
03/25/1910 : The "North Bank Road" is first used as a trademark by the Spokane Portland & Seattle Railway.
04/30/1910 : The Walla Walla Valley Railroad is incorporated.
07/01/1910 : Chicago Milwaukee & St. Paul Railroad operations begin from Tacoma to Mt. Rainier, Washington.
08/15/1910 : The Centralia to Grays Harbor, Washington line is opened and is shared by the Union Pacific & the Chicago Milwaukee & St. Paul Railroads.
10/15/1910 : Great Northern Railway changes the name of Wellington to Tye, Washington.
10/23/1910 : Northern Pacific Railway begin operations from Puyallup to Lake Kapousin, Washington. (2.7 miles)
11/24/1910 : The North Coast Railroad is absorbed into the Oregon Washington Railroad & Navigation Company.
12/23/1910 : The Oregon Railroad & Navigation Company is merged into the Oregon Washington Railroad & Navigation Company.
05/01/1911 : Tacoma, Washington's Union Station opens serving the Great Northern, Northern Pacific Railways and the Union Pacific Railroad.
05/01/1911 : The new Oregon Washington Railroad & Navigation Company station, opens at Tacoma, Washington.
05/28/1911 : The Chicago Milwaukee & St. Paul Railroad's "Olympian & Columbian" passenger trains begin service from Chicago Illinois to Seattle, Washington to compete with the Northern Pacific Railway.
06/15/1911 : Carl R. Gray president of the Spokane Portland & Seattle Railway, becomes president of the Spokane & Inland Empire Railroad.
10/31/1911 : Oregon Trunk Line Railroad's first regular train departs from Fallbridge, Washington for Bend, Oregon.
07/01/1912 : James J. Hill resigns as chairman of the Great Northern Railway.
10/17/1912 : The Bellingham & Northern Railway Company is incorporated.
02/08/1913 : The Great Northern Railway receives its first motor car.
03/04/1913 : Great Northern Railway puts its first observation car into service.
06/14/1914 : The North Yakima & Valley Railroad is merged into the Northern Pacific Railway.
06/25/1914 : The Connell Northern Railroad company is sold to the Northern Pacific Railway.
06/25/1914 : The Port Townsend & Southern Railroad is sold to the Northern Pacific Railway.
09/14/1914 : Union Station opens in Spokane, Washington, and is used by the Oregon Washington Railroad & Navigation Company and by the Chicago Milwaukee & St. Paul Railroad.
09/15/1914 : Union Pacific Railroad operations begin from Ayer to Spokane, Washington.
09/30/1914 : The Great Northern Pacific Steamship Company is formed by the Great Northern & Northern Pacific Railways.
12/15/1914 : Northern Pacific Railway operations begin from Tenino to Tacoma, Washington, via the Point Defiance line.
01/17/1915 : Chicago Milwaukee & St. Paul Railroad's Snoqualmie Tunnel opens for traffic.
02/19/1915 : Northern Pacific Railway's second track from Lester to Easton, Washington opens.
01/22/1916 : A snow slide destroys a snowshed at Embro, Washington & a bridge at Cores, Washington at Stevens Pass on the Great Northern Railway.
05/29/1916 : Gerat Northern Railway owner James J. Hill dies.
06/17/1916 : The Spokane Portland & Seattle Railway's first passenger timetable is issued.
11/04/1916 : Northern Pacific Railway operations begin from Harrah to White Swan, Washington. (9.3 miles)
12/28/1917 : President Wilson takes control of all U. S. railroads because of World War One.
01/11/1918 : Northern Pacific Railway operations begin from Weikel to Tieton Washington. (6.7 miles)
01/09/1919 : The Spokane & Inland Empire Railroad goes into receivership.