Question: Where crushed limestone trail trail  follow the Chicago, Rock Island and Pacific Railroad, also known as Rock Island Line or The Rock?
Context: The Central Midland Railway (reporting mark CMR) , a division of Progressive Rail Incorporated of Lakeville, Minnesota, is a short line railroad in the U.S. state of Missouri, operating under lease of the former St. Louis Subdivision of the Chicago, Rock Island and Pacific Railroad.  CMR operates the eastern-most 60 miles of the 298-mile Rock Island line which used to stretch from St. Louis to Kansas City, Missouri.  Today, CMR's operation of the line is performed under two separate leases from the Union Pacific Railroad and the Ameren Corporation, respectively, from Overland, Missouri - a suburb of St. Louis, to a location just west of Union, Missouri.  CMR's first leased-segment is Union Pacific's "Lackland Subdivision" which extends from "Rock Island Junction" near the intersection of Page Avenue and I-170 in Overland to a location on the north-side of Creve Coeur Lake in Maryland Heights, Missouri, known as "Vigus."  The second leased-segment is owned by Ameren and extends from Vigus to Pleasant Hill, Missouri, with active service terminating just west of Union. Peru – LaSalle Station was a Chicago, Rock Island and Pacific Railroad station situated between the towns of Peru and LaSalle, Illinois.  The station building—which still exists as a lawn and garden center—is located on the north side of the track, on 1st Street.  LaSalle/Peru was the original eastern terminus of the Rock Island Line, as it first traveled from Rock Island, Illinois to connect with the Illinois and Michigan Canal.  "The Rock" was eventually liquidated, and now the track is operated by CSX, with the Iowa Interstate Railway getting some service via trackage rights. "Rock Island Line" is an American folk song.  Ostensibly about the Chicago, Rock Island and Pacific Railroad, it appeared as a spiritual as early as 1929.  The first recorded performance of "Rock Island Line" was by inmates of the Arkansas Cummins State Farm prison in 1934. The Sayre Rock Island Depot is a historic railroad station located at 106 E. Poplar Ave. in Sayre, Oklahoma.  The depot was built in 1927 along the Chicago, Rock Island and Pacific Railroad (a.k.a. Rock Island); it replaced Sayre's original Rock Island station, which opened outside the town limits in 1901.  The new station is just two blocks north of downtown Sayre.  It accommodated the increased traffic the line had gained in the early 1920s; it also helped the railroad compete with the recently designated U.S. Route 66.  The station building was built from and has an Italian Renaissance Revival design.  Its design resembles two other surviving Rock Island stations in Oklahoma: the Hobart Depot and the Walters Depot. The Chicago, Rock Island and Pacific Railroad (CRI&P RW, sometimes called "Chicago, Rock Island and Pacific Railway") (reporting marks CRIP, RI, ROCK) was a Class I railroad in the United States.  It was also known as the Rock Island Line, or, in its final years, The Rock. The Rock Island Depot is a historic railroad station on Arkansas Highway 11, between North Prairie and North Livermore Streets in Hazen, Arkansas.  It is a single story stuccoed brick building with Mediterranean style, built in 1915 by the Chicago, Rock Island and Pacific Railroad (aka the "Rock Island Line").  Its main facade is oriented south, toward the former railroad tracks, with a projecting telegrapher's booth.  It is topped by a tile roof with broad eaves supported by large brackets. The EMC AB6 was a type of diesel locomotive built exclusively for the Chicago, Rock Island and Pacific Railroad (the "Rock Island Line") by General Motors' Electro-Motive Corporation and delivered in June 1940.  Two examples were built, numbered #750 and #751.  They were built for the "Rocky Mountain Rocket" passenger train, which travelled as a unified train from Chicago, Illinois, to Limon, Colorado, but then divided; with one section going to Colorado Springs, Colorado, and the other to Denver, Colorado.  The Rock Island desired a locomotive that could look like an integrated part of the train during the Chicago-Limon portion of the route, but could then be operated independently to take three cars to Colorado Springs.  A regular, cab-equipped A-unit could have been purchased, but that would have ruined the streamlined look of the train, so the RI had EMC build a flat-fronted locomotive based on an E-series E6B (B unit) but with an operating cab, headlight, pilot, and other features to enable it to operate as an independent locomotive. The Rock Island Spur of Katy Trail State Park is a state park in the U.S. state of Missouri that is 47 mi rails to trails hiking and biking trail.  Work on the trail was completed and the trail was opened on December 10, 2016 .  The trail provides residents of the Kansas City region direct trail access to the 240 mi Katy Trail State Park, the longest rails to trails trail in the U.S.  The Rock Island Trail uses "abandoned" (embargoed and out of service) right-of-way of the Chicago, Rock Island and Pacific Railroad between Pleasant Hill in Cass County and Windsor in Henry County where it meets the Katy Trail. The Hoover Nature Trail (HNT) is a crushed limestone rail trail in eastern Iowa that follows the old Chicago, Rock Island and Pacific Railroad route between Burlington and Cedar Rapids.  The trail is a shared-use trail for bicycling, hiking, jogging, walking, cross-country skiing, and nature study and is 24 mi long. The EMC-TA was a model of Diesel locomotive produced for the Chicago, Rock Island and Pacific Railroad by the Electro-Motive Corporation in 1937.  The original six "Rock Island Rocket" streamliners were three- or four-car stainless-steel semi-articulated trainsets built by Budd Company, powered by six identical locomotives, #601-606.  The locomotives were classified as model TA—the T indicating Twelve hundred hp (890 kW), the A indicating an A unit (cab-equipped lead locomotive).  The Rock Island Line was EMC's only customer for the TA locomotive model.
Answer: The Hoover Nature Trail