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I will be covering this portion of the Union Pacific from west to east since most of my trips across the territory were made in that direction. I'll also cover a small portion of the Chicago Northwestern at the east end of Nebraska. From the time the railroad connected with the Central Pacific to the end of the century, the UP was only able to add about 17 miles of second track. With increased traffic and the leadership of Harriman the railroad transformed the single track Overland Route to mostly double track by the end of 1918. Double track was extended west from Kearney to Julesburg around 1912. The first mention of automatic block signals on the UP was in 1898. Block signals are spaced 1.25 miles before a switch and up to three miles apart on open stretches. In January 1908, the UP had 1,189 miles of automatic block signals, plus 694 miles on the Oregon Short Line and 352 miles on the Oregon Railway and Navigation Company. In 1909, UP installed automatic block signals from Columbus to Silver Creek. At the end of 1914, it had automatic block signals on 653 miles of single track and 818 miles on double track east of Salt Lake City, plus 520 miles on single track and 107 miles on double track on the OSL, plus 603 miles on single track and 23 miles on double track on the OWR&N. In 1930, it added an electric interlocking at Julesburg, CO to control 3 power switches and 8 signals. In 1936 UP was in a program to replace semaphore signals on the double track main line between Ogden and Omaha. It installed 34 US&S color light signals Waterloo to Ames and 11 US&S color light signals Richland to Columbus. Most of the semaphore signals had been installed around 1905. At the time traffic was 18 passenger and 18 freight trains a day. During 1942 the UP did extensive work replacing semaphore signals with US&S color light signals. North Platte to Cheyenne got 298 signals on 224 miles of double track. Kansas City to Topeka got 125 signals on 65 miles of double track. Topeka to Manhattan, KS got 76 signals on 50 miles of single track. With the dramatic increase in coal traffic from the Powder River Basin, triple track between O'Fallon and Gibbon was completed in August 1999.