From the crossovers at Borie (MP 519.1), where the speed limit is 55 mph and the connector (actually, the beginning of the Greeley subdivision) to West Speer diverges on the south side, Tracks 1 and 2 head just south of due east, Two Main Tracks, CTC, speed limit 55 mph, turning just north of due east, past detectors at MP 517.1, Corlett, Colorado Junction, where the line from Greeley originally trailed in to the south, and a spur at Wycon (MP 514.5), where Tracks 3 & 4 come alongside to the south, to the crossovers at CP W511 (MP 510.8), where the speed limit is 40 mph and Tracks 3 & 4 trail in on the south side.
From West Speer (MP 519.7), where the connector from Borie trails in from the northwest and Track 4 begins (i.e., now 2MT, CTC, on this alignment), southeast and then east to the 6,756 ft. center siding at the junction at Speer (MP 518.3), the west apex of a large wye, Tracks 3 & 4 head just north of due east, on the north leg of the wye, to the junction with the east leg of the wye from Speer Junction and the crossovers at East Speer (MP 517.2), and then north, past where the original routing of the line from Greely headed away north-northwest, and turns just north of due east, alongside Tracks 1 & 2, to the crossovers at CP W511 (MP 510.8), where the speed limit is 40 mph and Tracks 3 & 4 trail in on the south side of Tracks 1 & 2.
The two sets of 2MT (now 4MT) pass beneath the through truss bridge carrying the former Colorado & Southern line between Denver and Wendover overhead, to reach the west end of the yard on the south side at Cheyenne (MP 509.5), where the speed limit is 35 mph, with the roundhouse and shop used by the UP steam program on the south side of the line, between the main tracks and the yard, and the former passenger depot on the north side, turning southeast at the east end of the shops and yard tracks, as all the yard tracks trail in on the south side, to East Cheyenne (MP 508.4), where the 4MT become 3MT and a spur, the rump of the very original route from Greely (from 1870 to 1908), heads off south, with the main line turning just south of due easy, with the route of an erstwhile CB&Q line just to its north, to the crossovers at Barnett (MP 506.5), where that line once crossed the UP main to head away southeast, the UP main reduces to 2MT and turns east-northeast, and the speed limit rises to 70 mph.
The line is now climbing Archer Hill, turning just north of due east, east, east-northeast past the crossovers and 6,045 ft. south side siding at Archer (MP 501.4), northeast, east-northeast past detectors at MP 499.0, crossovers at CP W497 (MP 497.7) and Durham, east past crossovers and spur at Hillsdale (MP 491.0) and detectors at MP 489.0, southeast and then just south of due east past crossovers at Burns (MP 482.8) and crossovers at CP W481 (MP 480.7), and east-southeast to the wye junction, on the north side, with the Yoder branch to the north and 10,805 ft. siding on the north side at Egbert (MP 477.6 - MP 475.4), east past detectors at MP 475.3, Tracy, and crossovers at CP W469 (MP 469.5), northeast past CP W467 (MP 467.4) to the spur at Pine Bluffs (MP 465.6), and just north of due east past the border between Wyoming and Nebraska.
There are crossovers at CP W459 (MP 459.4), a turn east-northeast, Bushnell (MP 456.2), a turn east, detectors at MP 454.3, Oliver, a turn just north of due east, crossovers at CP W449 (MP 448.5), a turn east along the south side of Lodgepole Creek, the 6,357 ft. center siding and shuttle-enabled rail-served grain elevators at Kimball (MP 445.6 - MP 443.6), crossovers and the 10,472 ft. north side siding at Owasco (MP 439.4 - MP 437.2), Dix (MP 435.4), detectors at MP 434.6, Jacinto (MP 430.8), CP W426 (MP 426.4), a bridge over Lodgepole Creek to its north side, crossovers at Potter (MP 423.9), a turn east-southeast, detectors at MP 416.1, the junction with the line from the Huntsman Industrial Center (and formerly from the erstwhile Big Sioux Ammunition Depot) trailing in on the north side, and shuttle-enabled rail-served grain elevators at Brownson (MP 415.5), a turn to the east, crossovers and 11,315 ft. north side siding at Sidney (MP 410.2 - MP 407.9), where there is a connector south to the BNSF Northport to Sterling coal line, and a bridge carrying that line overhead.
The main line continues east, along the north side of Lodgepole Creek, past Colton (MP 401.0), detectors at MP 397.1, Sunol MP 396.3), and crossovers at CP W392 (MP 392.0), turning east-southeast, still following the creek, past CP W390 (MP 390.0), a spur at Lodge Pole (MP 389.7), detectors at MP 384.8, CP W382 (MP 382.0), and shuttle-enabled rail-served grain elevators at Chappell (MP 380.3), and turning south-southeast, still following the creek, past crossovers at CP W378 (MP 377.4), Ralton, detectors at MP 372.5, the border between Nebraska and Colorado, and Wolf, where it turns east to the junction with the line trailing in from Sterling and Denver on the south side at Julesburg (MP 365.2), where there are crossovers, a 10,854 ft. siding on the south side and a 9,509 ft. siding on the north side, all along the north side of the South Platte River, as the line turns east-northeast.