Much of the line is operated by CTC, in 2005. The southern part of the Shasta Route is divided into the following subdivisions:
· Valley subdivision from Roseville to Dunsmuir
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 East Valley line runs north through Marysville and Binney Junction (where the former WP Feather River line crosses the former SP line). Since the UP/SP merger, connecting tracks have been added at Binney Junction to facilitate all four possible routings through that junction. Most "I-5 Corridor" trains operate this way, since they make calls at the ex-SP Roseville Yard on the southeast side of the Sacramento to Roseville line, just west of the major line junction at the east end of Roseville. At that junction, Washington (MP 106.6, on the northernmost track—track 1—only), the line over Donner Pass continues northeastward while the line towards Binney Junction turns (initially) northwest.
The Valley subdivision is single track, CTC, over its entire length, with a speed limit of 30 mph through the junction and 65 mph thereafter. An east-north connecting track from Yosemite on the Donner Pass line's track 1 trails in at Sierra (MP 107.1), there is a Hold Signal at Andorra (MP 108.2), where the line turns north and the speed limit rises to 79 mph for passenger trains and 70 mph for freights, a 6,370 ft. siding at Sunset Whitney (MP 111.4-113.1), the speed limit falls to 55 mph through Lincoln (MP 116.5), where the line turns northwest, and a detector at MP 116.9, and then rises to 60-55 through Clayton (MP 118.4) and Ewing (MP 121.0) to the 8,260 ft. siding at Brock (MP 121.6-123.6). The speed limit rises to 65 mph through the siding and 79-70 thereafter. From Brock, the line heads north-northwest through Sheridan and then northwest again across the Bear River bridge to Wheatland (MP 128.1), Erle (MP 131.2), whence a spur heads northeast to Beale AFB, and the 8,350 ft. siding at Ostrom (MP 132.7-134.4).
The line then passes a detector at MP 136.4, Rupert (MP 138.9), Dantoni Junction (MP 139.8), where a spur heads west to the ex-WP line and the speed limit falls to 30 mph, and Marysville (MP 140.8), where the line turns north and the speed limit rises to 45-40 through Binney Junction (southeast connectors at MP 141.8, flat crossing, and northeast connectors at MP 142.0), where teh ex-WP line crosses and the connector from the northbound/eastbound ex-WP line to the northbound ex-SP line trails in on the west side of the line.