The Bogies had their issues, too, very exposed when the South Park pushed into Platte Canyon and the Leadville boom took off in 1878. Grades, sharp curves and immense traffic overcame the railroad's ability to keep up and leasing D&RG and AT&SF Baldwin 2-8-0s woke the line up. Twins of these engines were quickly ordered. Several Brooks engines outlived the Bogies, thanks to upgrades in the '90s, and proved useful on the "flatter" portions of the line--Morrison, Gunnison to Pitkin during the winter tunnel closures and even the runs from Buena Vista up to St Elmo during these shutdowns.
The Boulder papers were particularly harsh on the Colorado Central and South Park Brooks leased by the Greeley Salt Lake & Pacific between 1885 and 1894 (about 8-9 of the Brooks rotated on and off the GSL&P), at times calling out their poor pulling capacity or lack of maintenance and demanding the UP step up and send better engines.