In Southern Pacific days, this line running geographically north south for most of its route was nonetheless described as (railroad) east going away from San Francisco and (railroad) west heading towards San Francisco. UP has changed at least some of this usage to north/south, reflecting the actual geography, where appropriate.
The line is single track operated by CTC. The southern part of the Shasta Route is divided into the following subdivisions:
· Valley subdivision from Roseville to Dunsmuir
· Black Butte subdivision from Dunsmuir to Klamath Falls
After a short westerly stretch during which it crosses the Feather River, the East Valley line runs north-northwest from Binney Junction (MP 142.0, where the former WP Feather River line crosses, and across which there is a 25 mph speed limit), through quite low-level countryside, much of it barely above the water table, in the bottomland of the Sacramento River valley. North of the junction, the speed limit is 70 mph. The line crosses over the Feather River just north of the junction. Highway 99 runs alongside to the west. There is an 8,450 ft. siding at Berg (MP 144.4-146.1), a grade crossing at which Highway 99 crosses to the east side and continues to run alongside the line on that side, a spur at Sunset (MP 149.8), a detector at MP 150.5, the former Sacramento Northern crossing from south (west of the line) to north (east of the line) at Live Oak (MP 151.5), and an 8,420 ft. siding at Fagan (MP 154.1-155.8).
There is a grade crossing, a lumber mill on the west side, and three more grade crossings. The line passes through Gridley (MP 158.0), where the former depot is on the west side of the line, and Biggs (MP 161.4), where there are several grain elevators alongside the line. There is a detector at MP163.9, followed by Riceton (MP 164.1). There is an 8,185 ft. siding at Richvale (MP 167.2-168.9), , a grade crossing next to an agricultural facility, more rice paddies, and rail served grain silos on the south side, followed by Durham (MP 178.1), where the erstwhile Sacramento Northern route is adjacent on the east side, a detector at MP178.3 on a gradual curve to the northwest, another grade crossing, bridges over irrigation channels, three more grade crossings, a bridge overhead, and Barber, where an SP branch to Stirling City once headed east.
At Chico, where there is a grade crossing just south of an 8,540 ft. siding from MP 182.1 to MP 183.7, there is another grade crossing, extra industrial tracks on the east side, and an original SP passenger depot and freight house on the east side of the track at MP 184.1. Following two grade crossings, the Sterling City Industrial Lead leaves at MP 184.9. There is a small yard named Barber Yard at MP 185.1. Six more grade crossings, four of them still within the town of Chico, precede a spur for GI Meal at MP 189.4, and another four grade crossings and sour tracks on the east side precede a detector at Nord (MP193.3), where the line turns north-northwest again. There are two more grade crossings, an 8,378 ft. siding at Anita (MP 192.2-193.9), another grade crossing and a road alongside to the east, the line crosses Deer Creek at Vina (MP203.0), there is a detector at MP 206.3, the line passes through Los Molinos (MP 209.7), where there is a grade crossing and a small town on the east side of the tracks, another grade crossing, a road underneath, and another grade crossing, as the line turns due west across the Sacramento River into Tehama (a location known to Union Pacific as “South Gerber”, MP 211.7), where there is a wye with the erstwhile SP “West Valley Line” heading south to Davis, now operated by the California Northern Railroad.
· Valley subdivision from Roseville to Dunsmuir
· Black Butte subdivision from Dunsmuir to Klamath Falls
North of Tehama, taking the north leg of the wye at South Gerber (MP 211.7), there is a road alongside to the east as the line again heads north-northwest with a 13,500 ft. siding across Elder Creek to Gerber (MP 214.9, elevation 261 ft.), followed by a grade crossing, a Wal-Mart Distribution center on the west side, major agricultural facilities on the east side, and another grade crossing, before passing through Proberta (MP 215.8) the 8,305 ft. siding at Rawson (MP 218.2-219.9, e. 286 ft.), another grade crossing, and Redbank (MP 221.0), with the road still alongside to the east. The line bridges over I-5, bridges over a main road, and bridges over another road, followed by four more grade crossings to Red Bluff (MP 223.4, el. 305 ft.). Fields give way to scrubland and then woodland/savanna. The line’s dead straight course across the bottomlands is now replaced by curves following the contours of the narrowing river valley, as the line turns north through Glade (MP 224.5, el. 319 ft.), northwest past the detector at MP 225.9, Blue Tent (MP 227.9) and the 8,345 ft. siding at Blunt (MP 228.6-230.3, el. 422 ft.), where there is a grade crossing.
The line continues generally north on a twisting course, past Hooker Hill (MP 232.4), el. 543 ft. to the 8,200 ft. siding at Draper (MP 235.6-237.3). There is a huge barn on the east side, two grade crossings, the line turns northeast across Cottonwood Creek at Cottonwood (MP 240.4, el. 421 ft.) as I-5 passes overhead, there is a road alongside to the southeast and industry to the northwest, two more grade crossings and the detector at MP 241.8, and the line turns northwest again over a grade crossing and through the 8,445 ft. siding at Culp (MP 243.2-244.9, el. 453 ft.). There is a wood products facility to the east, with spurs for wood products cars, a grade crossing, and I-5 passes overhead again. At Anderson (MP 247.1, el. 431 ft.), the former California, Shasta & Eastern once left in a northeasterly direction, there are two grade crossings, the Shasta County Fairgrounds to the west and another pair of grade crossings. There are wood products facilities on the east side, a spur on the east side, and another grade crossing with a street on the east side. At MP 251.5, the line turns due north, crossing a tributary before reaching the 9,245 ft. Girvan siding (MP 253.3-255.2, el. 464 ft.). There is then a bridge over a divided highway, a street alongside to the west, and two more grade crossings.
There is a passenger depot on the west side of the line at Redding (el. 554 ft.), with a 45 mph speed limit (from MP 258.6 to MP 258.7) in front of it, a helper track on the east side, and a road bridge overhead. The line turns northwest and then northeast, crossing the Sacramento River on a huge trestle that includes the curve northeastwards, along the 1930s Shasta Dam line diversion (away from the previous line alongside the Sacramento River that departed westward just before the beginning of the trestle). At the north end of the trestle, the line turns due north (although still curving), passing under a road bridge, through the 5,290 ft. siding at Silverthorne (MP 262.4-263.4, el. 720 ft.), and a detector at MP 264.2, and then turns north-northeast past the 5,095 ft. siding at Central Valley (MP265.7-266.7, el. 845 ft.), over a road passing below, and through the 9,350 ft. siding at Gray Rocks (MP 269.0-270.9, el. 1,019 ft.), with a major lumber mill on the east side at the north end of the siding, before turning north again to pass through 2,719 ft. tunnel 1 (MP 271.2) and 2,691 ft. tunnel 2 (MP 272.4) and then across the lower deck of the 3,588 ft. long, 500 ft high, Pit River Bridge (carrying I-5, once Highway 99, on the upper deck), opened along with the entire line deviation from Redding to Delta (to avoid the areas being flooded by Shasta Dam and Lake) on March 17, 1942.
On a short northeasterly stretch at the beginning of the line through the Lake Shasta area, the line passes through 1,864 ft. tunnel 3 (MP 273.8), 856 ft. tunnel 4 (MP 274.4), and 1,900 ft. tunnel 5 (MP 274.7) before turning northwest through 745 ft. tunnel 5 (MP 276.8). There is a road alongside to the east (maybe the northbound lanes of I-5) and a view of an arm of the lake to the east before reaching 1,688 ft. tunnel 7 (MP 277.5), the 6,120 ft. siding at Obrien (MP 277.0-278.2, el. 1203 ft.), 897 ft. tunnel 8 (MP 278.8), a trestle across an arm of the lake, 1,610 ft. tunnel 9 (MP 279.9), passing across the Salt Creek Trestle, through Mead (MP 281.0, el. 1134 ft.) and 2,243 ft. tunnel 10 (MP 281.2) and across the Sacramento River Trestle, which also crosses over a road on the north side of the lake.
Turning northeast along the west bank of the river, above the route of the original line (usually below water level, below), there is a detector at MP 283.2, the line crosses a sidearm of the lake and turns northwest alongside the lake, crossing over I-5 on a bridge, and passing Intermediate Signals, to the 8,300 ft. siding at Lakehead (MP 284.2-285.9, el. 1,151 ft.) in mixed forest dotted with campgrounds in the Sacramento River Canyon, crossing the river and passing 941 ft. tunnel 11 (MP 288.1), Intermediate Signals, and 916 ft. tunnel 12 (MP 288.4), crossing the river again and turning northeast alongside the river. There is a grade crossing with a dirt road that then crosses the river on a bridge, right at the curve.
Back on the original line, trains pass through the 5,255 ft. east-side siding at Delta (MP 296.2-297.3, el. 1,137 ft.), and pass Intermediate Signals, There is a 5,570 ft. west-side siding at Lamoine (MP 299.1-300.3, el. 1244 ft.), , the line crosses the river twice, there is a grade crossing at a spot where I-5 soars high overhead within the 4,970 ft. west-side siding at Gibson (MP 303.2-304.2, el. 1,386 ft.), I-5 crosses overhead again at the north end of the siding (because the siding curves through an entire semi-circle between the I-5 bridges), with old Route 99 following the line on the west side. The line crosses the river before 647 ft. tunnel 13 (MP 305.5), which has a short snowshed on the north end, passes Intermediate Signals, and crosses the river again on a through girder bridge before Intermediate Signals and then a detector at MP 307.4, crosses the river twice more, and passes through an 8,300 ft. west-side siding at Sims (MP 308.6-310.2, el. 1,666 ft.) that has a north-facing spur on the west side near the south end and a grade crossing within it. The line crosses the river into 698 ft. tunnel 15 (MP 310.5) and crosses the river again leaving it, both on through truss bridges. There are Intermediate Signals and then a 5,385 ft. east-side siding at Conant (MP 312.7-313.9, el. 1,843 ft.). The line passes Dirigo (MP 316.1), el. 1,982 ft., the Falls Avenue grade crossing, another grade crossing, a detector at MP 316.5, and another grade crossing just within the 5,805 ft. west-side siding at Castle Crag (MP 318.0-319.2, el. 2,086 ft.), where the siding goes to the west of a pond west of the main track, before reaching South Dunsmuir at MP 319.6, el. 2,239 ft., at the south end of an 8,501 ft. siding and the former SP yard (of which there is little left), and the Dunsmuir X-Over (MP 321.4). The Dunsmuir Depot and Division Point is on the west side of the tracks at MP 322.1, el. 2,286 ft., with the remains of the roundhouse, the still-extant turntable, and the water tank painted to celebrate the glory days of the Southern Pacific on the east side. Speed limit is 25 mph through Dunsmuir.
From Dunsmuir, the line passes a grade crossing just within the north end of the siding at North Dunsmuir (MP 322.6), where the speed limit for freight drops to 20 mph, another grade crossing, a slide fence to the west, a bridge where I-5 passes overhead, and a detector at MP 323.2. At about MP 325.3, the line makes a sharp turn from northeast to northwest, following the west bank of the river and starts the climb out of the Sacramento River Canyon, passing a hold signal at Small (MP 326.4, el. 2,622 ft.) and another detector at MP 327.3, and then making a clockwise semi-circle while crossing the river at the loop at Cantara (MP 327.6, el. 2,778 ft.), heading southeast and climbing steeply on the east bank of the river. There is now a big tubular steel buttress on the east side of the line where it crosses the river at Cantara, to prevent another derailment like the one that caused the massive fish kill in 1992.
There are Intermediate Signals at MP 328.1, a slide fence to the west, and MP 330.1, another detector at MP 330.3 and another semi-circular curve, this one counter-clockwise at the upper edge of the canyon, leading back northwestward to South Mott (MP 331.0, el. 3,151 ft.), start of a 7,248 ft. siding to South Azalea-North Mott (MP 332.5), end of the first siding and start of a second, 5,700 ft. siding to North Azalea (MP 333.6, el. 3,347 ft.), where the speed limit rises to 40 mph. The line then turns due north, with I-5 alongside to the east, passes over a grade crossing, with a road now alongside to the east, passes over another grade crossing, I-5 crosses overhead, and there are two more grade crossings before the 4,337 ft. siding at Mount Shasta (MP 336.6-337.5, el. 3,553 ft.), with a grade crossing at Alma Street within the siding road alongside to the east. There are extra tracks on the east side where the McCloud River Railroad heads off to the east across the road, still within the siding. The main line turns northwest again, through the 8,670 ft. siding at Upton (MP 338.5-340.2, el. 3,717 ft.), where the speed limit rises to 50 mph, the road on the east side swings away, passes another detector at Deetz (MP 342.2, el. 3,799 ft.) and turns northeast. There is a grade crossing, I-5 passes overhead and the line turns north to reach the beginning of the 6,350 ft. siding at South Black Butte (MP 343.7).
At Black Butte (MP 345.2, el. 3,898 ft.), is the junction with the former SP Siskiyou line, now operated by the Central Oregon & Pacific (CORP), which goes off to the west, the north end of the south siding and the south end of the 5,400 ft. north siding, there is at least one extra track, perhaps two, on the west side, and on the east side of the line is an operable water tank, still used into the 1990s when steam-powered excursions ran.
· Black Butte subdivision from Dunsmuir to Klamath Falls
From Black Butte, where the north siding ends at North Black Butte (MP 346.4), the Natron Cutoff line runs across upland meadows, heading up a 1.3% grade around the northwest shoulder of 14,162 ft. Mt. Shasta, with the bucolic Shasta Valley below to the northwest. The line twists and turns to follow the contours as the line heads generally northeast, but at least one line segment points south or southeast for a short distance. There are Intermediate Signals at MP 350.x, a 5,065 ft. siding at Hotlum (MP 351.8-352.9, el. 4,126 ft.), where the speed limit is 35-30, a trestle over a valley, the speed limit rises to 40-35, a detector at MP 357.5, intermediate signals at MP 357.x,, and an 8,342 ft. west side siding at Andesite (MP 360.0-361.7, el. 4,596 ft.). The line heads a little west of due north, making Mount Shasta visible from the other side of a train for a short distance, and then passes a 5,675 ft. siding (MP 368.3-369.4, el. 5,063 ft.) at Grass Lake, where the speed limit is 40 mph, with the line's summit at an elevation of 5,122 ft., where the line turns generally eastward for a few miles. A detector at Erickson (MP 372.9, el. 5,017 ft.) precedes a 5,169 ft. siding at Penovar (MP 376.5-377.5, el. 4,812 ft.), where the speed limit is 70-60, with a grade crossing near the north end of the siding, Intermediate Signals at MP 379.0, and Intermediate Signals at MP 381.1. At Bray (MP 381.9, el. 4,646 ft.), where a former logging railroad left to the east, the line turns northeast, with speed limit falling to 50-40, past Intermediate Signbals at MP 383.x, and at about MP 384 turns northwest, affording a view of Mount Shasta from the side of a train that is otherwise away from the mountain. After the 8,343 ft. east side siding at Kegg (MP 385.6-387.2, el. 4,461 ft.), where the speed limit is 60-55 through the siding and 70-60 to the north of it, the line turns north past a detector at Jerome (MP 390.9, el. 4,323 ft.), Intermediate Signals at MP 392.7, a 7,286 ft. siding at Mount Hebron (MP 393.2-394.7, el. 4,259 ft.), and a grade crossing.
At MacDoel (MP 396.7, el. 4,242 ft.), the line turns north-northeast, with US 97 alongside to the west, for almost all of the rest of the way into Klamath Falls. There are two grade crossings, a detector at May (MP 404.7, el. 4,237 ft.), a 5,439 ft. siding at Dorris (MP 406.1-407.2, el. 4,241 ft.), a grade crossing within the town of Dorris, a sawmill on the east side of the line, and another grade crossing, 2,076 ft. tunnel 17 (MP 407.8), a run on a ledge above farmland below to the east, and 1,145 ft. tunnel 18 (MP 410.0) on a curve to the west around a bluff, with the line again up on a ledge above farmland to the east.; the speed limit along the ledge is 55-50
The line crosses the California-Oregon state border, and passes a detector at MP 411.0, the speed limit returns to 70-60, and the line reaches the 4,858 ft. siding at Worden (MP 415.4-416.2, el. 4,122 ft.), back on the north-northeasterly heading. There are Intermediate Signals at MP 417.9, a grade crossing, a grain elevator on the east side of the line, US 97 is now alongside to the east, having crossed the line in the town of Dorris, the line passes through Midland (MP 422.3, el. 4,095 ft.) on a fill in marshland along the east side of Lower Klamath Lake (or what was once Lower Klamath Lake), with US 97 also running on a fill on the east side of the line. There is a grade crossing on the north side of a bridge over an irrigation canal, and a detector at MP 424.1, with US 97 passing overhead right at the detector, a grade crossing and the Klamath River to the east, before reaching Texum (MP 426.2, el. 4,095 ft.), the wye junction with the former SP Modoc line from the southeast (now closed as a through route) to Winnemucca, NV, a hold signal at South Klamath Falls (MP 427.4), where the speed limit falls to 55-40, CTC ends and Yard Limits Absolute Block begins, and Bieber Line Junction (MP 427.6), where the BNSF (ex-BN, ex-GN) High-line to Bieber and Keddie (the latter portion ex-WP) departs to the southeast and the speed limit falls o 50-40. There are BNSF spurs on the west side of the line, to logging facilities across the Klamath River, and a passenger platform track to the west, with a handthrow switch at the south end.
There are Intermediate Signals at MP 427.9 and MP 428.6, and the ten-track ex-SP Klamath Falls freight yard (MP 428.7, el. 4,094 ft.) is also on the east side, immediately north of Bieber Line Junction. A highway crosses overhead on a bridge. The Klamath Falls UP yard office is on the west side of the line with the Amtrak depot on the west side of the line (MP 429.9, el. 4,105 ft.), across from the north end of the UP freight yard. The speed limit through this area is 25 mph.