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Idaho, Northern & Pacific Railroad: Comprising Ex-UP Branches

Last revised: September 3, 2024

By: Adam Burns

The Idaho, Northern and Pacific Railroad (reporting marks INPR) is a short line based out of Emmett, Idaho.  It operates roughly 210 miles of ex-Union Pacific Railroad branch lines (three in total of various mileage) in the southwestern Idaho and eastern Oregon.

The railroad is a fairly recent upstart having begun operations in 1993 when it purchased the lines from UP, which was looking to shed much of its secondary trackage in the area.

The history of these lines date back to the early 20th century as the UP took over smaller companies.  The IN&P today is currently a subsidiary of the Rio Grande Pacific Corporation.

The history of many of the Union Pacific's Idaho (and Oregon) lines date back to the Oregon Short Line Railway, a subsidiary of the UP created in 1881 as a means of providing the shortest route between Wyoming and Oregon.

It was renamed the Oregon Short Line Railroad after the UP fell into bankruptcy in 1893 although by 1898 had regained control of the railroad.

The Oregon Short Line was mostly created through outright purchase of other lines such as the Utah & Northern Railway, Payette Valley Railroad, and the Oregon Railway & Navigation Company.

Ultimately, the OSL would comprise the UP's main line to Portland and also be the catalyst for its many branches in all three western states (Idaho, Washington, and Oregon).

Interestingly, the OSL remained on UP's books until it was dissolved in 1987 and soon after the Class I began looking to shed access trackage in the region, mostly branches and secondary lines which radiated away from its main line.

On November 15, 1993 three of its branches were transferred to Rio Grande Pacific which created the newly formed Idaho, Northern and Pacific Railroad:

• Its branch between Elgin and Joseph, Oregon (63 miles); its branch between Payette and Emmett (a distance of 30 miles).


• Its branch between Emmett and Cascade (a distance of 72 miles, although the line would be abandoned the rest of the way north to McCall, an additional 34 miles).

At this point the short line operated a system covering 165 miles and after operating these lines for four years the short line elected to abandon the Elgin to Joseph segment in 1997.

However, this was purchased by Wallowa County which created the Wallowa Union Railroad Authority, which still operates the branch today.

Shortly thereafter, Union Pacific sold to the Idaho, Northern and Pacific Railroad the rest of the branch between La Grande and Elgin, a distance of 21 miles which it continues to operate today.

Additionally, two years after the short line abandoned the La Grande Branch it picked up two more UP branches in 1999; the Caldwell to Wilder line (a distance of 11.5 miles) and the Nampa to Hillcrest branch, which also serves Boise (a distance of 24.8).

Today, the IN&P continues to operate these lines giving it 159.3 miles of railroad it owns directly.

Additionally, it has trackage rights over the Union Pacific along its main line between Nampa and Weiser, a distance of 59 miles which enables the short line to directly connect to its Idaho branches.

In total, the IN&P operates some 218.3 miles of track.  The Idaho, Northern & Pacific Railroad itself is broken down into two divisions; the Idaho Division and Oregon Division and its sole connection is with the UP in three different Idaho locations including Payette, Nampa, and Weiser as well as La Grande, Oregon.

Its current traffic base includes timber products, chemicals, and agricultural products (wheat, grain, etc.).

Locomotive Roster

It also once hosted a tourist train, the Thunder Mountain Line.  However, citing declining ridership trips were suspended for the 2016 season.  

When in service the train utilized a series of five FP10s (formerly F3s), adorned in a beautiful red livery with gold trim.

The tourist line’s featured events included rafting expeditions (“river and rail” which means you take a trip up the rapids, are dropped off, and then ride back down the river) and dinner trains, just to name a few.