At the crossovers at Springville X-Over (MP 695.8), the branch to Spanish Fork and Elberta turns away to the southwest, and the main lines turn southeast. The single tracks of the Utah Railway and the former D&RGW are operated as paired track (Two Main Tracks, CTC) from here east to Helper. The Rio Grande track ("Track 1"), the more northerly of the two, turns south, south-southeast and then south again, past a spur on the north side at Gomex (near where the tracks come back together), while the more southerly Utah Railway track ("Track 2") turns southwest and then southeast, past Sutro (MP 690.7), before turning south alongside the Rio Grande track. The line turns south-southeast at Mapleton, south and then east-southeast past detectors at MP 685.3, where the speed limit has fallen to 60-45, crossovers at Castilla X-Over (MP 684.7) and Castilla (MP 684.5), on Track 1 only.
By now, the line is on the diversionary route further up the northern hillside, with the highway even further up the hillside to the north, past the former site of Thistle, buried in a 1983 mudslide that was bypassed by means of two new tunnels, built in the span of less than four months. The mudslide cut off any access to the Rio Grande branch south to Marysville, which was closed from that date. The old highway and old roadbed are visible in the valley below, both west and east of the mudslide. The diversionary line turns south, past detectors at MP 681.8, and east through the 3180 ft. (Track 1) and 3009 ft. (Track 2) Thistle Tunnels (MP 681.0), past another set of detectors at MP 680.3 and another set at MP 677.2, returning to the original right-of-way at the crossovers at Rio X-Over (MP 676.7), where the speed limit is 40-35.
From here eastward, the grade increases as the line starts the serious climb to Soldier Summit, and the speed limit increases to 55-35, as the line turns east-southeast past the crossovers at Narrows X-Over (MP 672.3), Mill Fork, the highway to the north, a stream in the valley to the south, and detectors at MP 668.1, where the speed limit is again 40-35, and turns east to Detour (MP 665.3), where the speed limit falls to 30 mph. Originally, the line continued along the valley floor at this point (generally along the alignment now occupied by the highway through this area), and then made a very steep climb to the summit, but a later diversion reduced the grade substantially, and the line now diverts onto the north side of the valley, past a highway bridge overhead, from the north side to the south side of the line, a dirt road grade crossing, Intermediate Signals, the line climbing above the road to the south, and a dirt track grade crossing, turning south and then east, along the north side of the valley, Intermediate Signals, and extra track on the south side trailing in, and climbs through the loops at Gilluly, making a clockwise horseshoe, beneath the highway bridge overhead (since the highway has now risen above track level) and the original line location, past the 7,900 ft. siding at Gilluly (MP 661.9-659.8), within which it turns back west on a shelf on the south side of the valley, climbing well above the road by the place the siding ends, turning southwest after the siding ends, past a dirt road grade crossing, and making an anti-clockwise horseshoe around a bluff, back northeast, past Intermediate Signals, and then east, on a shelf further up the hillside than the previous one, angling south-southeast, past Intermediate Signals, north, and then east, past more Intermediate Signals, still above the original alignment.
The diversion ends at the crossovers at West Summit (MP 651.9), where the speed limit is 40-30 and the line turns southeast, past a dirt road grade crossing, to reach Soldier Summit (MP 651.4, el. 7,440 ft.), where the speed limit rises to 60 mph, and south past the crossovers at East Summit (MP 650.1), where the speed limit rises to 65-60. The line then drops down, past a dirt track grade crossing, detectors at MP 647.4, Intermediate Signals, a minuscule Price River or its tributary alongside to the south, a grade crossing, and the crossovers at Colton X-Over (MP 644.8), with four extra tracks alongside to the south, towards the east-flowing Price River, reached definitively at Colton (MP 644.4), whence a branch formed out of those extra tracks climbs south up the river valley to various coal mines, the main line turns due east, into a valley, and the speed limit falls to 35 mph. The line now runs in a narrow canyon, alongside the river, first turning northeast on its north side, and then turning southeast, beneath a highway bridge overhead, across the river to its south side, past Intermediate Signals, and then east across the river again, and around several curves in both line and river, to the crossovers at Kyune (MP 640.1-638.9), with a highway bridge overhead from southwest to northeast between the crossovers, where line and river turn south, a spur from Greystone Quarry once trailed in from the north, and one to Porters Quarry once left to the east at Jennings Junction.
The line continues south, across the river, through the 410 ft./468 ft. Kyune Tunnels (MP 638.7), and back across the river, with the highway now to the south/west again, turns east, past Intermediate Signals, and makes a clockwise horseshoe back to the southwest, south again, with the river just to its west and the highway beyond, through the 409 ft./351 ft. Nolan Tunnels (MP 636.1), south-southeast past a dirt track grade crossing, Intermediate Signals at MP 636.0, Nolan, Intermediate Signals at MP 634.0, the crossovers at Lynn X-Over (MP 632.7), where the speed limit falls to 30 mph, and Lynn (MP 632.0, Track 2 only), and south across the river again, to the south/west side of the river, with the highway still to the west of the line, past detectors at MP 630.5, through Castle Gate (MP 630.4), where the rock formation on the west side of the river was blasted away to make room for the line and/or highway on that side, leaving only the one on the east side of the river, crossing the river to the east side again, past a detector at MP 630.5, a grade crossing at the coal mine on the east side of the river, a bridge back over the river, and Intermediate Signals at Panther, to Utah Railway Junction (MP 628.8), where there is a signal bridge, the double-track Utah Railway heads away to the southwest and the Rio Grande line, still 2MT, CTC, continues south, across the river to its east side again, turning south-southeast at the crossovers at West Helper X-Over (MP 627.3) past a grade crossing, and Kenilworth Junction, where a spur to Kenilworth Mine once headed east, and turning south at Spring Canyon Junction, whence a branch west up Spring Canyon once left to cross the river, past a bridge over a street, to the north (west) end of Helper Yard, on the east side of the line, and the passenger station at Helper (MP 626.4), with its depot on the west side of the line.