completely bypass the heavy grades of the pass was prohibitively expensive, the railroad compromised by boring a shorter, tunnel at the elevation. To bring the tracks to the elevation of the tunnel, the railroad line included a switchback on each side of the summit; trains ascending the pass would pull into the first switchback, run backwards through the summit tunnel, and then reverse direction again at the switchback on the opposite side. Descending Bannock Pass, the railroad followed a narrow canyon into Idaho's Lemhi Valley and the small agricultural community of Leadore, some from Armstead. The G&P's repair shops were at Leadore, and it also marked a junction point for the railway. The main line continued northwest from Leadore for another , following the broad valley and the Lemhi River downstream through fertile farming and ranching land to the county seat of Salmon. Salmon was the line's terminus, and by far the largest town on the G&P route, with a 1910 population of 1,434. The only branch line operated by the G&P began at Leadore and headed southeast, following the Lemhi River valley upstream about to the town of Gilmore, near the upper end of the valley. Gilmore in 1910 was the center of a prosperous silver and lead mining district, and was thus a major source of early traffic for the railroad. Operating history When the G&P began service in 1910 the railroad owned a total of 8 steam locomotives, 16 passenger cars, 250 freight cars, a rotary snowplow, and other miscellaneous pieces of equipment; except for some of the freight cars, all equipment was acquired second-hand. When service began that May, the G&P scheduled a tri-weekly passenger train between Armstead and Salmon, leaving Armstead on Mondays, Wednesdays, and Fridays and returning on the following days. Freight trains also operated on most days. Traffic levels proved lower than expected, however, and in 1913 the separate freight and passenger services were replaced by a tri-weekly mixed train, carrying both freight and passenger equipment. Both passenger and freight traffic declined in later years, and beginning in 1922 mixed train service was partially supplanted by a Brill railbus, a self-propelled vehicle designed to carry passengers and small freight shipments. For most of the 1920s, the railbus operated between Salmon and Gilmore, while the tri-weekly mixed continued between Salmon and Armstead. In 1931, the G&P borrowed a second, larger railbus from the Northern