The route is divided into the following subdivisions:
Fallbridge subdivision from (Portland and) Wishram to SP&S Jct
Lakeside subdivision from SP&S Jct to Pasco (and Spokane)
From Wishram (MP106.1), where there are Two Main Tracks, CTC, the speed limit is 60 mph, the depot (and stuffed-and-mounted GN 4-8-2, now under a roof but still in the open air) is on the north side of the tracks, and the small yard is on the south side of the tracks, adjacent to the river, the line heads east along the north bank of the river, the two main tracks reduce to single track, CTC, and the speed limit rises to 70 mph for passenger trains and 60 mph for freights, through 385 ft. tunnel 12 (MP 108.1), as the line turns southeast and then east-northeast along the course of the river, opposite the mouth of the Deschutes River to the south, with an island mid river, and past the 7,092 ft. siding at Maryhill (MP 113.8). This whole stretch of line is on a shelf alongside the river at the base of basalt cliffs separating it from the high country to the north. The “river” along here comprises wide stretches of flat, apparently lifeless water penned up behind the various dams. There is no sense of the flow of a great river. The UP is visible across the river as far as Sage.
The line continues past Hewett (MP 117.6), Cliffs (MP 118.6), where there is a spur to an aluminum plant to the north, and John Day dam blocks the river to the south, the speed limit rises to 79-60, past the 9,136 ft. siding at Towal (MP 125.0), where the line turns east, a detector at MP 128.0, where the line turns southeast, Goodnoe (MP 130.7), where the line turns east again, the 7,099 ft. siding at Bates, and Sundale (MP 140.4). The line turns northeast, past the 8,459 ft. siding at Roosevelt (MP 147.8), where the speed limit falls to 70-60, and then east-northeast, past a detector at MP 152.2, where the speed limit is again 79-60, Moonax, the 7,103 ft. siding at McCredie (MP 157.7), where the speed limit falls to 70-60 again, and Alderdale (MP 182.3). The line turns northeast and then just south of east, to run around the backside of an island in the river, and then east-northeast again at the 9,126 ft. siding at Whitcomb (MP 170.4).
There is a ballast track at Whitcomb Point, as the line turns northeast, Sage (where the UP line across the river turns away from view), where the line turns east-northeast again, a detector at MP 177.2), where the speed limit rises to 79-60 again, , a 7,052 ft. siding at Paterson (MP 179.8), the line turns east-southeast, away from the river for a short distance, and then east along the river again, past Longview, back from the riverbank again past a detector at MP 190.8 and the 9,351 ft. siding at Plymouth (MP 192.0), and along the riverbank again at North McNary, adjacent to the McNary dam on the river. The line curves east-southeast and then starts a big slow curve around to the east, east-northeast and northeast, past the 7,015 ft. siding at Berrian (MP 203.3), McAtinger, a detector at MP 207.8, and Tomar.
The line follows the Columbia around to the north, past the 9,352 ft. siding at Yellepit (MP 215.8), and then northwest, bridging over an inlet and then leaving the riverbank in a northwesterly direction, past Finley (MP 223.9), a flat crossing with a UP branch, and the 7,932 ft. siding at Hover (MP 228.5) to reach Kennewick, as the line turns north, and SP&S Jct. (MP 229.7), where the speed limit is 35-25 and the line joins with the ABS ex-NP main line heading north-northeast, where it crosses the river on the Columbia River bridge (MP 229.9), where the speed limit is 35 mph, into Pasco. The former SP&S line turns east-southeast immediately on the north side of the bridge, with a further connection to that line at West Wye Junction (MP 146.3 on the ex-NP line), a spur from trackage along the left bank of the Columbia River trails in, and the north leg of the wye with the ex-SP&S line to the east is at Pasco (MP 145.6/231.4), where the depot is on the west side of the line north of the wye, as the ex-NP line it is on turns north-northwest, and the major yard at Pasco is on the east side of that line extending north from the area of the depot.