Improvement of the standard gauge main line through Utah to relieve congestion had begun in 1898, when the RGW added a second track to the steep 4% grade to Tucker on the west side of Soldier Summit. The shallower east-side grade was similarly doubled to Colton in 1906, and further to Kyune and from Castle Gate to Helper in 1909. Construction began on a new low-grade line west of the summit in 1912, when the D&RG added a track between Detour (the west end of the realignment) and Thistle. The new line, with a double hairpin curve, was completed the next year, as was a second track between Kyune and Castle Gate, completing a double-track line between Thistle and Helper, with a maximum grade of 2.4% on the east slope and 2.0% on the west. Local competition arrived in 1912, when the United States Smelting, Refining and Mining Company, which owned coal mines southwest of Price, organized the Utah Railway (originally the Utah Coal Railway). U.S. Smelting objected to the D&RG's charging of higher freight rates due to the mines' location on a branch line, and began to build its own line over Soldier Summit into the Utah Valley. The two companies reached an agreement in November 1913, where the D&RG would operate the Utah Railway between a junction near Castle Gate and the mines, and the unfinished line between Thistle and Provo would be completed as a second track. This arrangement began with the completion of the road in 1914, and the D&RG now had a double-track line between Provo and Helper. Three years later, the Utah Railway began independent operations between the mines and Provo under a reciprocal trackage rights arrangement that has persisted to the present, where each company allows the other to use its half of the double-track line.