At Grand Forks Junction, the railway diverged north from the VV & E's main line with spurs from the passenger depot and to the Granby Smelter north of Grand Forks.  the Phoenix Branch then looped west to ascend the July Creek, now partially Highway 3.  Remnants of it can still be seen as you head out of Grand Forks heading to Greenwood. The route climbed counter clockwise and finally skirted Montezuma Hill to enter Phoenix from the west.  Length was about 39 km. 

The Great Northern Railway had surveyed routes to Phoenix and the Granby Smelter, but construction was delayed by other railways and local landowners.  the branch was not opened for service until 1905.  Experiencing easier grades than the CPR's Phoenix Branch from Eholt, GN was able to handle heavier trains and soon became the major carrier of Phoenix ores.

Falling post-war copper prices and a coke strike spelled the end of the Phoenix Branch in 1919 and the Granby Smelter spur was removed the following year. 

From Curlew, the Great Northern Railway followed the Kettle River Valley to Midway and ascended the Myers Creek  to Myncaster before looping north toward Dumont.  The climb continued with Baker Creek, through Bridesville across the International Border to a summit at Molson, Washington.  From Molson, the railway skirted Molson and Sidley Lakes and descended with Ninemile Creek to Oroville, Washington. 

Diverging from Curlew on Great Northern's 1902 line from Grand Forks to Republic, GN's Washington and Great Great Northern Railway began construction up the Kettle River in 1905, inaugurating operations to Ferry, Washington on the International Border by the end of the year.  

In 1906, Great Northern announced intention to continue westward construction to Vancouver to form a Third Main Line.  Using its 1897 VV&E  charter in Canada, GN built through Midway and Bridesville before returning to the United States once more as the W & GN through Molson and Oroville. 

Great Northern inaugurated operations to Molson in 1906 and to Oroville in 1907, when regular passenger service from Spokane was introduced.  Although the Third Main Line was completed in 1916, the railway failed to operate through service from Spokane to Vancouver.  the steep Molson to Oroville section was abandoned in 1931, removed in 1932 and the Curlew to Molson section through British Columbia followed in 1935.