recently restored steamer is part of the vaunted K-37 class. They were perhaps the largest, heaviest, strongest class of narrow gauge Mikados ever to work a narrow gauge railroad, with the possible exception of a couple of articulateds on the Uintah.
Starting life in 1902 as a Baldwin-built standard gauge locomotive for the Rio Grande numbered 1026, she was converted along with 5 other classmates to 3-foot narrow gauge in 1928. Additionally, Burnham shop machinists took her from a 2-8-0 wheel arrangement (Consolidation) to a 2-8-2 wheel arrangement, known as Mikado. The innovators in Denver's Burnham shops had no way of knowing that their work would long outlast the thundering, Big Boy-like articulated engines of the 2-8-8-2 L-131 class that saw work in the very same shops!
Yet, some parts of 491 make her twice as unique an engine. Colorado Railroad Museum intern Benjamin Fearn explains in the museum's Iron Horse News, the firebox of 491 has thermic siphons installed inside. Such devices worked to take more of the energy from the combustion in the fire and pass it into the water of the boiler. As it does, convection draws more water into the siphon to pick up more energy. Conservation and efficiency were useful concepts at Burnham, just like most steam shops of their day.
So, if everything goes right, 491 could be 13 years away--as a narrow gauge engine--in what could be a career not measured in years, but in centuries. As my favorite engine at the museum, I can't wait to see the completed work!
The story of the restoration of 491 is available in the Iron Horse News and in the museum's Roundhouse News blog.◊
Special thanks to John Hill for the timely photograph!