Authority to occupy the main track is dispatched via CTC from West St. James to South Butterfield. From there, track warrant control (TWC) is used, and it is dark territory until Le Mars, Iowa, where automatic block signaling is used in conjunction with TWC. Union Pacific has trackage rights over CN's track from Le Mars to Sioux City, although UP dispatchers grant the authority to occupy the main track.
Accidents
On November 18, 1999, an empty northbound Union Pacific grain unit train was stopped on the main track at Carnes to meet a southbound UP manifest train which was to take the siding. For reasons unknown, the southbound train did not enter the siding and struck the stopped northbound train head-on, derailing 30 cars, five locomotives, and claiming the life of 23-year-old conductor Paul Schmidt of Boone, Iowa on the southbound train. Dale Evans, the driver of a crew transport van parked nearby was also killed.[6] This accident was a prompt for legislation for the implementation of Positive Train Control, which could have prevented the accident.[7]
On May 16, 2021, a Union Pacific manifest train bound for North Platte, Nebraska derailed and caught fire in Sibley, Iowa. The derailment involved 47 cars which were carrying asphalt, hydrochloric acid, and potassium hydroxide.[8] Approximately 80 people were evacuated from a 2.5 mi radius around the derailment site, and the derailed cars were allowed to burn for nearly two days. No injuries or deaths occurred.[9]