UP Mill Creek Bridge (Dunlap)

In 1867, the Cedar Rapids & Missouri River Railroad (CR&MR) continued constructing a mainline westward from Boone, Iowa.  In the late 1850s and early 1860s, the CR&MR had participated in constructing a line from Clinton, Iowa to Boone.  The CR&MR was leased by the Chicago & North Western Railway (C&NW), which was seeking a route connecting Chicago to the Missouri River.  In 1867, an impressive 150 miles were constructed between Boone, Iowa and Council Bluffs, Iowa, completing a connection between Chicago and the Missouri River.  The line also allowed for a short spur from Missouri Valley, Iowa to the Missouri River opposite of Blair, Nebraska.  This spur would eventually be extended across the Missouri River and into Nebraska.  Between 1869 and 1872, Union Pacific Railroad (UP) constructed a bridge across the Missouri River between Council Bluffs and Omaha, Nebraska; and the C&NW obtained trackage rights over the bridge to reach Omaha.  During the second half of the 19th Century, the C&NW had constructed and acquired a large amount of trackage throughout the Midwest.   In 1884, the CR&MR was formally purchased by the C&NW; and this line quickly became a core asset of the C&NW system.  

By the late 19th Century, traffic over this line had increased to the point significant upgrades were required.  In 1893, a 5-mile section of railroad was relocated west of Jefferson, Iowa to improve grades and eliminate curves.  One of the most significant barriers to efficient operation over this line was the Des Moines River Valley between Boone and Ogden, Iowa.  The original route crossed the Des Moines River at Moingona, which was approached by winding and steep approaches on each bank.  In 1899, C&NW subsidiary Boone County Railway (BCR) began construction on a more direct route between Boone and Ogden, Iowa; including a massive viaduct across the Des Moines River.  The BCR was consolidated into the C&NW in 1900, and the new cutoff was completed in May 1901.  The new alignment shortened the route by 3 miles, cut grades in half and only required two small curves.  The original mainline through Moingona was maintained as an emergency backup and to serve industries in the area.  Between 1901 and 1902, a second track was also constructed between Ogden and Council Bluffs, including a 5-mile realignment near Arcadia, Iowa.  The double tracking of this line provided the C&NW with a well constructed double track mainline between Chicago and Council Bluffs.  

By the 20th Century, the C&NW was operating an extensive railroad network, which radiated north and west from Chicago.  The original mainline into Moingona was abandoned in 1930.  This line served as the backbone of the C&NW, connecting transcontinental freight and passengers at Omaha to Chicago.  Known as the Overland Route, this line became one of the most significant railroad routes in the United States.  This route saw continuous upgrades during the 20th Century, including significant bridge, rail, tie and signal upgrades.  In 1995, the C&NW was purchased by UP, which provided UP with a mainline into the railroad hub of Chicago.  Into the 21st Century, the line has seen continuous upgrades, and remains one of the most significant railroad lines in the United States.  Today, UP operates this line as the Boone Subdivision between Boone and Missouri Valley; and the Omaha Subdivision between Missouri Valley and Council Bluffs.