From the junction on the north side of the Sunset Route in Yard Limits at Lordsburg (MP 1146.4, el 4,250 ft.), where the speed limit is 10 mph, the line heads west-northwest, past a runaround track on the east side, a bridge over a culvert, a dirt track grade crossing, a spur on the west side, a double-track loop and a further loop in between the branch and the main line on the west side of the branch, the end of Yard Limits at MP 1148.5, the end of UP property at MP 1150.0, where the speed limit rises to 30 mph under Track Warrant Control, as the line heads out over a flat (but not quite level) plain with sparse scrubby vegetation, MP 1151, a bridge over an arroyo, a dirt track grade crossing, a bridge over drainage, Veitch (MP 1157.2), and Sand Spur, to Summit (MP 1165.3, el. 4,220 ft.), where there are old stock pens on the east side and a dirt track grade crossing.
The line turns curvily just west of due north and descends at 0.7%, past MP 1169, a bridge over an arroyo, MP 1170, MP 1171, a deck girder bridge over an arroyo (MP 1171.2), a dry watercourse on the west side with flash flood barriers, a bridge over an arroyo, Foster, and a dirt track grade crossing, and across the border between New Mexico and Arizona (MP 1175.3) past Thomson (MP 1176.2), a bridge over an arroyo, MP 1177, a bridge over an arroyo, two dirt track grade crossings, MP 1180, two dirt track grade crossings, a bridge over an arroyo, Franklin (MP 1180.8), two dirt track grade crossings, MP 1182, a dirt track grade crossing, US 70 alongside to the east, an angled grade crossing with US 70 (MP 1183.3), three dirt track grade crossings in town, US 70 alongside to the west, a grade crossing at SR 75, and Duncan (MP 1184.3, el. 3,640 ft.).
There are two grade crossings, two dirt track grade crossings, a grade crossing, and a dirt track grade crossing, and the line turns very curvily northwest, as it enters the Gila River valley, past a bridge over an arroyo, a dirt track grade crossing, a bridge over an arroyo, a track on the west side at Fox (MP 1186.9), where the speed limit has fallen to 20 mph, with a steep hillside to the west, MP 1188, and a bridge over an arroyo, and then curvily just west of due north, along the west bank of the river (which has water in it, here), with bluffs to the west, past a bridge over an arroyo, a dirt track grade crossing, a (silent) detector at MP 1189.7, MP 1191, a dirt track grade crossing, a bridge over an arroyo, Sheldon (MP 1192.3), a bridge over an arroyo, a dirt track grade crossing, MP 1193, a bridge over an arroyo, a dirt track grade crossing, a bridge over an arroyo, a dirt track grade crossing, MP 1197, where the speed limit drops to 10 mph, and a bridge over a gulley.
The line now runs through rocky narrows, below cliffs to the west, past a bridge over a gulley, and York (MP 1199.1), turning very curvily west-northwest, following the river on a ledge along its south side, past MP 1201, a bridge over an arroyo, a concrete road bridge overhead, and then immediately a steel arch bridge overhead (US 191 @MP 1203.5), MP 1204, and a bridge over a gulley, and then north, bridging over the river on a deck girder bridge (MP 1205.0), past a detector and extra track on the west side at Guthrie (MP 1205.2, el/ 3,415 ft.), and then climbing the cliffs on a ledge above the north side of the river, with more cliffs above the ledge, reaching the top of the cliffs above the river by MP 1206.
The line leaves the river heading northeast, still climbing along a ledge with cliffs to the east (but no longer above the river), past a dirt road grade crossing, MP 1207, and an embankment, turning very curvily northeast, past a bridge over Owl Canyon (MP 1207.3), curvily north, past a bridge over a gulley, and over the top of the watershed at MP 1209, top of grades in both directions, descending between 1% and 2%, curvily north-northeast, and curvily just west of due north past the 2,149 ft. west side siding at South Siding (MP 1209.8), with extra track on the west side near the north end of the siding, a bridge over a gulley and a bridge over a culvert, curvily west, through a rocky cutting and beneath the concrete arch bridge carrying Old Safford Road (MP 1210.7), and curvily north past an embankment, a rocky cutting, two embankments, and North Siding (1211.5), with excavations visible to the north across the San Francisco River valley as the line turns north-northeast.
An embankment leads directly into 336 ft. Tunnel 6 (MP 1212.1), which (like all the others) has no portal structures and is cut through bare rock, exiting directly onto another embankment, with the line passing a rocky cutting and turning curvily northwest past an embankment, a rocky cutting, curved 262 ft. Tunnel 5 (MP 1212.8), embankment, rocky cutting, embankment high above the San Francisco River, MP 1213, embankment above river, and rocky cutting, and curvily north past an embankment, a rocky cutting, and an embankment directly to 326 ft. Tunnel 4 (MP 1213.3), where the descent steepens, past a curved embankment, a rocky cutting with (to the west) an adjacent abandoned cutting, 245 ft. Tunnel 3 (MP 1213.6), exiting directly onto a curved embankment, and passing a rocky cutting with an adjacent abandoned cutting, and another rocky cutting.
There was once a siding at Smelter, as the descent continues past a dirt road grade crossing, an embankment, and a short cutting into 152 ft. Tunnel 2 (MP 1214.4), past a bridge over a gulley, a short cutting, and an embankment directly into 163 ft. Tunnel 1 (MP 1214.5), exiting onto a ledge, and passing a short cutting a ledge, a short cutting, and an embankment, turning curvily northeast past facilities to the east at Gatti, and curvily north, past the bridge carrying US 191 overhead (MP 1215.0) and bridging over Wards Canyon Road (MP 1215.2), passing a grade crossing into the town as US 191 comes alongside to the west, past a grade crossing, a grade crossing at 2nd Street, a grade crossing, and the flood gates (MP 1215.7).
The line bridges over the San Francisco River (MP 1215.9), crossing US 191 at grade (MP 1216.0), and passing the junction (MP 1216.1) where the Morenci Industrial Railway (a Phelps-Dodge property) from the Morenci Open Pit Mine, trails in on the west side, below cliffs to the west with US 191 to the east, with extra track on the east side, crossing US 191 at grade again (MP 1216.2), and turning north-northwest to the five-track east-side yard at Clifton (MP 1216.3), where the speed limit is 5 mph in Yard Limits, and there is an extra track on the west side at the two-storey brick depot, a grade crossing at the north end of the yard, and the end of the branch at MP 1216.7, where the erstwhile Clifton Smelter once was, a line once continued west to West Clifton and a narrow gauge line to Evans Point once continued north.