From the 12,307 ft. siding at Paradise (MP 64.1), where the depot is on the north side of the tracks, and the remains of the yard on the south side, west of the junction, the 4th subdivision to Missoula via St. Regis turns away to the south over a long bridge over the Clark Fork River, and the Flathead River joins the Clark Fork River (which comes in from the south), the MRL 10th subdivision over Evaro Hill turns east-southeast, along the north side of the Flathead River, single track, unsignaled, with speed limit 35 mph at Paradise. This is the original NP main line from 1883, and was supplemented at a later date by the significantly longer water-level line along the Clark Fork River through St. Regis. The 10th subdivision is operated by Track Warrant Control.
The line and river turn south and then east, past Knowles and the 720 ft. long Perma Bridge over the Flathead River, turning east-northeast, with the line now on the south side of the river, past a spur at Perma (MP 51.6), where the speed limit is 40mph, and turning just south of due east along the Flathead River as it ascends past McDonald (MP 44.6), where the speed limit has risen to the line's maximum 49 mph, and the line enters the Flathead Indian Reservation, the 4,489 ft. siding at Dixon (MP 37.8), where there is a wooden depot on the south side of the track, and the MRL 11th subdivision, from Poison at the south end of Flathead Lake, turns away to the north, following the river which does likewise on the west side of that line.
The main line continues just south of due east, past a detector at MP 33.7).and a spur at Ravalli (MP 30.8), where it turns curvily south-southeast, through Flathead, and then turns south past the 3,400 ft. siding at Arlee (MP 21.1), where the speed limit is 35 mph, east and then south through Schley, jogging west-southwest and then just west of due south to the 2,161 ft. siding at Evaro (MP 10.5), 3,908 ft. elevation, where it heads southwest, there used to be a wye on the east side of the track for turning helper locomotives, and the speed limit drops to 25 mph for the descent of Evaro Hill, turning just west of due south and then east-southeast past Nagos (MP 5.4), south, crossing the 226 ft. high, 797 ft. long, Marent Trestle, southwest, south-southwest, east, south, west, and south again, turning southeast at DeSmet (MP 0.0), where there is a La Forge grain silo on the north side of the tracks as the line trails into the north side of the 4th subdivision, still running along the Clark Fork River.